mpp msc abstracts

							                         DEPARTMENT OF
                   MYCOLOGY & PLANT PATHOLOGY

                           M.Sc. THESIS ABSTRACTS


1.       Name of the student and           Som Dutt Sharma (S-83-A-6-M)
         Admission No.
2.       Name of Major Advisor             Dr. V.K.Gupta
3.       Title of Thesis                   Persistence and degradation of fungicides in
                                           apple soil
4.       Year of completion of Degree      1985
5.       Abstract of Thesis

         Out of three fungicides, Hexathir and Bavistin persisted upto 60 and 120 days,
respectively in both the sterilized and unsterilized soil, whereas Aliette persisted upto 120
and 90 day, respectively under these conditions at room temperature. After 120 days,
Bavistin was recovered at a level of 8.83 and 7.75 ppm in case of 200 and 100 ppm in
sterile soil. In case of Aliette and Hexathir too, the recovery was more in sterilized soil.
The degradation of all the fungicides was faster in the soil where microbes were added. In
all the fungicides degradation increased with increase in temperature, it was minimum at
5oC and maximum at 25oC. Aliette was degraded faster at pH 4.0 and degradation
increased with increase in soil pH and was minimum at pH 8.0. At pH 4.0, the growth of
Phytophthora cactorum was 27.30 and 28.33 mm in post and pre-treatments on 10th day,
which at pH 8.0 was 40.33 and 41.00 mm, respectively. Under different soil moisture
levels, Hexathir was found to be affected most by changing moisture levels followed by
Bavistin. Study on soil microflora was affected by the fungicides reveals that Bavistin at
200 ppm gave the maximum reduction of soil microflora followed by Hexathir.
1.       Name of the student and          Satyendra Prasad Singh (H-83-A-6-M)
         Admission No.
2.       Name of Major Advisor            Dr. R.D.Sharma
3.       Title of Thesis                  Studies on blight disease of gram (Cicer
                                          arietinum L.) caused by Ascochyta rabiei (Pass.)
                                          Lab.
4.       Year of completion of Degree     1985
5.       Abstract of Thesis

        The disease caused extensive losses (40.8 - 50.0%) in different locations of H.P.,
maximum being in Nalagarh area. Oat meal agar was the best solid medium for the
growth of the pathogen. Various isolates of the pathogen differed in their pathogenicity.
The pathogen overwinters in plant debris. Optimum temperature for the growth of the
fungus is 20oC and pH in the range of 7.5 to 8.5. Glucose and ammonium nitrate were
the best carbon and nitrogen source, respectively. Early sowing of the crop resulted in
disease escape. Calixin seed dressing along with sprays gave effective control of the
disease. Out of 125 lines screened against this disease, only 3 were comparatively
resistant.
1.       Name of the student and           Sudheer Kumar (S-83-A-7-M)
         Admission No.
2.       Name of Major Advisor             Dr. K.D.Verma
3.       Title of Thesis                   Studies on apple scab caused by Venturia
                                           inaequalis (Cke.) Wint. with particular emphasis
                                           on storage scab
4.       Year of completion of Degree      1985
5.       Abstract of Thesis

        Storage scab produced small, smooth, brown to jet black circular spots, often
shiny having intact cuticle. Artificial dip inoculation did not help in establishment of scab
in storage. Scabbed apple fruits played no role as source of infection to healthy fruits in
storage. Incipient scab infections carried by fruits prior to harvest resulted in scab
development during storage. Red Delicious was highly susceptible to storage scab than
Starking Delicious whereas, Golden Delicious was the least susceptible. Scab lesions
served as the mode of entry for secondary rotting fungi. Preharvest fungicidal sprays
proved effective in suppression of scab and rot development in storage. Delan (500 ppm)
was most efficacious followed by Dithane M-45 (3000 ppm). The postharvest dip
treatments with fungicides did not exhibit marked suppression of storage scab on test
cultivars, however, significant suppression of storage rot(s) was encountered in storage.
1.       Name of the student and          K. Ram Gopal
         Admission No.
2.       Name of Major Advisor            Dr. J.L.Kaul
3.       Title of Thesis                  Studies on blue mould rot of pear caused by
                                          Penicillium expansum Thom
4.       Year of completion of Degree     1985
5.       Abstract of Thesis

        Survey of markets and collection contents around SNS Complex, Nauni, revealed
six to eight per cent fruit losses. Injuries caused by different means provided the main
avenues of penetration and infection. The entry through open lenticels and stylar end(s)
was selective. Maximum vegetative growth was recorded at 25oC and sporulation at
30oC. Neutral pH (7.0) yielded maximum vegetative growth and sporulation. Among
nutrients, glucose supported maximum vegetative growth and sporulation, whereas,
arabinose and mannitol proved poor sources for vegetative growth and sporulation,
respectively. The exogenous supply of nitrogen sources revealed that potassium nitrate
supported the maximum growth and sporulation of the fungus. Susceptibility to blue
mould also increased as the fruit matured. Fruits of sand pear on artificial inoculation
(Penicillium expansum) were significantly less susceptible than China pear. The
polygalacturonase (PG) and polymethyl galacturonase (PMG) enzyme activity was
significantly higher in diseased than healthy tissues. Pre-harvest sprays with 1000 ppm
thiabendazole gave significant control of the blue mould rot in dip inoculated pears. The
relative efficacy of different fungicides revealed that all the systemic and non-systemics
gave good control as protectant (pre-inoculation treatment) than as eradicant (post-
inoculation treatment). The systemic fungicides were more efficacious than non-
systemics. Thiabendazole (1000 ppm) provided maximum disease control as eradicant
and protectant.
1.       Name of the student and         Mulk Raj
         Admission No.
2.       Name of Major Advisor           Dr. G.K.Gupta
3.       Title of Thesis                 Studies on the factors affecting the development
                                         of pseudothecia of Venturia inaequalis the apple
                                         scab pathogen
4.       Year of completion of Degree    1985
5.       Abstract of Thesis

        Early leaf fall in June, July and August was associated with increased leaf decay
and a resultant reduction in weight, area and pseudothecial productivity. Longer survival
of leaves fallen in September, October and November was linked with maximum
production of pseudothecia, though the leaves fallen in September were more conducive
for early maturity of pseudothecia and better productivity of ascospores than being from
leaves of other two months. Maximum production of pseudothecia was obtained on the
leaves of Golden Delicious and in descending order on Red Delicious, Granny Smith,
Tydeman’s Worcester and Red Gold. Quantitative production of primary inoculum of
Venturia inaequalis was also affected by the orchard height. Only one third pseudothecia
was obtained at lower elevation of 1364 m.a.s.l. at Kullu in comparison to what was
obtained at 2727 m.a.s.l. (Narkanda). Shady portions of the orchard favoured better
pseudothecial productivity, early maturity and higher percentage of ascospore emission.
When moisture was not a limiting factor, temperature had a marked effect on the
development of pseudothecia, asci and their maturity. Low temperature of 4 and 8 oC
were favourable for the productivity of pseudothecia in apple infusion agar plates.
1.       Name of the student and          Anand Prashar (S-83-A-1-M)
         Admission No.
2.       Name of Major Advisor            Dr. A.K.Sood
3.       Title of Thesis                  Studies on brown spot of soybean (Glycine max
                                          (L.) Merr.) caused by Septoria glycines Hemmi
4.       Year of completion of Degree     1986
5.       Abstract of Thesis

         Brown spot on soybean caused by Septoria glycines was prevalent in the Kangra
district of Himachal Pradesh. It was not present in Mandi, Kullu, Solan and Sirmour
districts. In yellow seeded cultivars the infected leaves turned yellow before shedding
whereas in green seeded cultivars there was no characteristic yellowing. Potato dextrose
agar and yeastal potato dextrose agar supported maximum growth. Growth was
maximum in Subouraud’s medium among the liquid media studied. Czapek Dox medium
supported maximum growth among different synthetic media. For growth and sporulation
of the fungus the optimum temperature and pH were 20-25oC and 6.0, respectively. The
conidia of S. glycines germinated between a temperature range of 20-32oC. The optimum
temperature for germination was 24oC. Spore germination on sterile water and leaf
exudates was similar. The periodic disease development was more when there was more
rainfall. Brown spot was found to reduce soybean yields from 18.3 to 23.0 per cent.
Topsin-M (0.03%), Agrozim (0.03%), Bavistin (0.03%) and Dithane M-45 (0.20%) were
found to contain the disease most effectively in the field. Out of 1617 and 615 varieties/
cultivars/germplasm line tested during 1984 and 1985 seasons, none was found resistant
to brown rot.
1.       Name of the student and           Bhag Ram Thakur
         Admission No.
2.       Name of Major Advisor             Dr. R.K.Yadava
3.       Title of Thesis                   Resistance to powdery mildew (Erysiphe
                                           polygoni D.C.) in pea (Pisum sativum L.)
4.       Year of completion of Degree      1986
5.       Abstract of Thesis

        Out of four Winsconsin lines the two viz., Wisconsin 7101 and 7104 were
observed to resistant whereas the other two viz., Wisconsin 7102 and 7103 remained
moderately resistant, while varieties Bonneville and Kinnauri were found to be
susceptible; Lincoln and GC-195 being highly susceptible during 1984-85. The 28 single
crosses involving the above lines/varieties inter se developed during this programme
behaved in a manner that reflected the dominance of susceptibility over resistance. The
cuticular and epidermal cell wall thicknesses were found to be more in resistant isolines
than in susceptible cultivars. All the F1’s derived from the susceptible x susceptible or
resistant x susceptible parents remained susceptible to the disease while the ones derived
exclusively from the resistant parents were, however, observed to be resistant and hence,
no epistasis. The total phenolic contents were observed higher in the leaves of resistant
isolines than in those of susceptible ones. The F1’s derived from the crosses involving
both resistant parents showed higher contents of OD phenols than those derived from
resistant x susceptible or susceptible x susceptible parents at different stages of disease
recording. The level of OD phenols was found to be higher in all resistant lines than in
the susceptible ones. The activity of polyphenol oxidase enzyme was found to be high at
Juvenile stage and increased at mild disease stage in all the 36 populations, but at severe
attack of the disease the activity of the enzyme was found to be nil in most of the
population. However, the enzymatic activity was observed to be higher in resistant
parents than in those of susceptible one. The F1’s derived from the crosses involving both
resistant parents had higher enzymatic activity than those derived from resistant x
susceptible or susceptible x susceptible at different stages of platn growth. The activity of
peroxidase was found to be higher in resistant lines than in those of susceptible cultivars.
All the susceptible cultivars had higher contents of ascorbic acid than those of resistant
isolines.
1.       Name of the student and          Rongseninla Aier (S-83-A-5-M)
         Admission No.
2.       Name of Major Advisor            Dr. P.K.Seth
3.       Title of Thesis                  Studies on olive green mould caused by
                                          Chaetomium globosum Kunze ex Steudel and
                                          Chaetomium olivaceum Cooke & Ellis on
                                          Agaricus bisporus (Lange) Sing. and its control
4.       Year of completion of Degree     1986
5.       Abstract of Thesis

        In the mushroom beds, development of mycelial spread was drastically checked
by the olive green moulds accompanied by delayed and poor pinning resulting in marked
reduction in yield. Studies on the response of the competitors to variable temperatures
ranging from 5-40oC indicated that maximum growth occurred at 25oC. Chaetomium
species could grow on a wide range of pH levels ranging from 4-10 pH. Studies on the
interaction of Chaetomium species with that of Agaricus bisporus exhibited no zone of
inhibition. Studies on germination of spores indicated that the optimum temperature for
both the competitors was 25oC. In pH studies on ascospore germination, 8 pH was
conclusively adjudged as the optimum pH for both the species. Survival under natural
conditions in soil indicated that the competitors could survive for a period of 7 months.
The spores and perithecia of the mould could survive in the refrigerator at 5-10oC as well
as at an ambient temperature of 15-30oC for a period of more than a year. In field trial,
six promising fungicides (5 systemics and one non-systemic) were evaluated to ascertain
their effect against Chaetomium species, as well as to record their effect on the yield of
the mushrooms. Results obtained indicated that Captan at 1000 ppm recorded the
maximum yield as compared to Bavistin, Benlate, TBZ, Topsin and Dithane M-45 at 250
ppm, which recorded yields lower than the control.
1.       Name of the student and           Arun Kumar Sud (S-84-A-20-M)
         Admission No.
2.       Name of Major Advisor             Dr. C.L.Bhardwaj
3.       Title of Thesis                   Studies on white rust of crucifers caused by
                                           Albugo candida (Pers) Kuntze.
4.       Year of completion of Degree      1986
5.       Abstract of Thesis

         The occurrence of systemic infection of white rust caused by Albugo candida on
Lepidium vir-ginicum and Capsella bursa-pastoris as well as local infection on Raphanus
raphanistrum as new host of white rust are first record from India. The local lesion
infection of white rust was mostly observed on abaxial leaf surface. The presence of
oospores was observed only in the systemically infected plant parts. Thirteen cultivars of
Brassica carinata, eighteen of B. napus and twenty six of B. juncea were found resistant
to all the six isolates of A. candida under study. Similarly, fifteen cultivars of B. juncea
were resistant against A. candida isolate from B. juncea out of three hundred and
eighteen cultivars. Nine new biological races were identified from nine isolates from
cultivated and wilt hosts for white rust. The fungicides Aliette 80 and Fuji 40 at 1000
µg/ml concentration (a.i.) were found effective in controlling the seedling infection by
soaking the seed for 16 hours. Similarly, in spraying method Katazin 48, followed by
Vitavax 50, Rabcide 30, Hinosan 50, Pervicur 70, Fuji 40 and Aliette 80 were found to be
effective in protecting the seedlings at cotyledonary stage even at lower concentrations
after 16 hours of sprayings.
1.       Name of the student and          Bipin Kumar Sharma (S-84-A-22-M)
         Admission No.
2.       Name of Major Advisor            Dr. P.K.Seth
3.       Title of Thesis                  Utilization of agricultural wastes for cultivation
                                          of Agaricus bisporus (Lange) Sing.
4.       Year of completion of Degree     1986
5.       Abstract of Thesis

         The investigations were undertaken on the utilization of different agricultural
wastes for the cultivation of Agaricus bisporus. At filling, the hydrogen ion concentration
of different composts from 8.48 to 8.62, at spawning 7.18 to 7.38, at casing 6.90 to 7.10
and at the end of cropping 6.10 to 6.20 which has more or less followed the trend of
control. Moisture content of different composts at filling ranged from 68.9 to 73.0, at
spawning 68.0 to 72.0, at casing 70.8 to 78.0 and at the end of cropping 65.0 to 72.0.
Different type of compost showed characteristics of a normal compost (control) with
respect to colour, texture and smell of ammonia, however, pine needle and saw dust
composts did not show the usual colour. The mycelium of A. bisporus could grow at a
faster rate in horse manure compost followed by control, sheep manure and corn stalk
compost, whereas, in other compost, it took comparatively longer period to acquire the
same growth. Studies on the pre-picking pattern of different composts indicted that
spawn run was completed in 15 days on all, except cattle manure, pine needle and
sawdust compost where it took 16 to 17 days. Yield data obtained from formulation I
clearly indicated that mean yield on horse manure and sheep manure compost was
statistically at par with the control. Comparative yield data from formulation II show that
corn stalk, corn cob and pea stalk composts were statistically at par with the control.
Yield on paddy straw compost was statistically different from corn stalk, corn cob, pea
stalk and control, however, indifferent from pine needle compost. Sawdust compost
yielded the least of all the substrates tried.
1.       Name of the student and         Rajesh Uppal (S-84-A-23-M)
         Admission No.
2.       Name of Major Advisor           Dr. R.D. Sharma
3.       Title of Thesis                 Studies on wilt complex of gram (Cicer
                                         arietinum) in Himachal Pradesh
4.       Year of completion of Degree    1986
5.       Abstract of Thesis

        Wilt incidence during the year 1985-86 ranged between 26.70 to 50.46 per cent in
various gram growing areas of Himachal Pradesh. Three pathogens namely, Fusarium
oxysporum f.sp. ciceri, F. solani and Sclerotium rolfsii were found associated with wilt
complex disease. Disease incidence was comparative more at seedling stage and
maximum at flowering and pod formation stage. The field and pot studies have shown
that crops sown in the middle of October can best endure/escape the wilt attack than
when even in the first week of November or sown before or after October month. Pre-
emergence mortality was effectively checked by Carboxin, Mancozeb and Captan but to
check post-emergence mortality carbendazim + Thiram (1:1) combination proved
superior. Out of one hundred and two cultivars/lines screened under natural condition in
the field and artificial condition in pot experiment, only ICC-5864 WR, ICC-10130 and
ICC-2506 were resistant to wilt attack.
1.       Name of the student and        Bhumeshwar Dutt (S-83-A-2-M)
         Admission No.
2.       Name of Major Advisor          Dr. L.N.Bhardwaj
3.       Title of Thesis                Studies on seed mycoflora of chick pea (Cicer
                                        arietinum L.) in Himachal Pradesh
4.       Year of completion of Degree   1986
5.       Abstract of Thesis

        In all nine fungi namely, Alternaria alternata, Ascochyta rabieii, Aspergillus
fumigatus, A niger, B. cinerea, Cladosporium cladosporiodes, Curvularia pallescens,
Penicillium sp. and Rhizopus sp. were found associated with the seeds of chickpea of
which A. rabiei was most predominant with maximum incidence of 35 per cent. Seeds
having moisture level below 7.5 per cent remained free from mycoflora than those
containing more than 8.5 per cent moisture. Seed dressing with captan, thiram,
carbendazim and benomyl eliminated most of harmful mycoflora associated with seed
including seed borne infection of A. rabiei and increased nodulation and germination
remarkably.
1.        Name of the student and            Ved Parkash Sharma (S-84-A-1-M)
          Admission No.
2.        Name of Major Advisor              Dr. S.K.Sharma
3.        Title of Thesis                    Impact of apple scab spray schedule on the
                                             incidence of foliar diseases
4.        Year of completion of Degree       1986
5.        Abstract of Thesis

        Spray schedule recommended for the control of apple scab by this university
consisting of eight sprays in a field trial reduced the intensity of all the foliar diseases and
controlled scab on apple leaves (97.97%), fruits (99.30%), powdery mildew (34.90%),
leaf spot diseases (85.12%), sooty blotch (89.91%) and fly speck (89.51%). Three
weather parameters namely, relative humidity (70-86%), temperature (17-26oC) and high
rainfall favoured the scab development both on fruits and leaves. Powdery mildew
appeared at the end of April and it was maximum in the month of June when the average
relative humidity mean temperature and total rainfall were 71.56 per cent, 25.01oC and
87.8 mm, respectively and decreased with increase in relative humidity and total rainfall
in July and August. Leaf spots and sooty blotch and fly speck diseases of apple were
maximum in the month of August and were positively correlated with relative humidity
and rainfall. The ascospore maturity of Venturia inaequalis started with the silver tip
stage and increased upto full bloom stage. Apple scab spray schedule suppressed the
ascospore production and pseudothecia formation and also checked the various foliar
diseases of apple to varying degree with a cost benefit ratio of 1:10:78. Captan, Dithane
M-45 and Syllit were the most toxic fungicides for pollen germination under in vitro
conditions and also under field conditions at full bloom and pink bud and full bloom
stage. MBC and thiophanate methyl were the safest fungicides to the pollen.
1.       Name of the student and          Harinder Raj Gautam (S-85-A-11-M)
         Admission No.
2.       Name of Major Advisor            Dr. V.K.Gupta
3.       Title of Thesis                  Studies on Phyllosticta leaf spot of pear
4.       Year of completion of Degree     1987
5.       Abstract of Thesis

        Leaf spot of pear caused by Phyllosticta piricola was found to occur from light to
severe intensities in different parts of Himachal Pradesh and appeared with the onset of
rain in the month of July. The disease intensity increased with high humidity coupled
with 25-30oC temperature and significant correlation of disease was observed with
relative humidity. Out of 11 varieties observed under natural epiphytotic conditions, none
was found resistant however, Kiefer was found least susceptible. Fungus grew best on
PDA and Richards’ solution. Optimum temperature i.e. 25oC and 6.0 pH supported
maximum growth of fungus in vitro. Sucrose and asparagine were the best source of
carbon and nitrogen for the growth of test pathogen, respectively. Mancozeb proved most
effective in inhibiting the mycelial growth of the pathogen in vitro followed by
carbendazim while thiophanate methyl was least effective. Under field conditions also,
four sprays of mancozeb (0.25%) and carbendazim (0.05%) were found highly effective
in reducing the disease index.
1.       Name of the student and           Rajeev Raina (S-85-A-13-M)
         Admission No.
2.       Name of Major Advisor             Dr. C.D.Thapa
3.       Title of Thesis                   Effect of some selected systemic fungicides on
                                           various fungi and nematodes associated with
                                           Agaricus bisporus (Lange) Sing.
4.       Year of completion of Degree      1987
5.       Abstract of Thesis

         The three systemic fungicides (Bavistin, Mertect and Topsin-M) were found to
have no phytotoxic effect on the spawn run (mycelial growth) of Agaricus bisporus when
sprayed at 50, 500 and 1000 ppm concentrations at the time of spawning/filling. The
fungal colonies in the beds treated with fungicides were drastically reduced as compared
with untreated beds. The fungicides were found to have some controlling effect on
mushroom nematodes, especially A. composticola. Mertect was highly effective followed
by Bavistin and Topsin –M. But the saprophagous nematodes were found to be least
effected by these chemicals. There was no residue of the sprayed fungicides in fruit
bodies harvested from the beds treated at 50 ppm at the time of spawning or casing stage
but it was detected in case of beds treated with 50 ppm concentration at pinhead stage of
the crop. There was increase in the residual content of fungicides with the corresponding
increase in their concentrations. Spray at pinhead stage resulted into high residual content
in all the fruit bodies treated at 50 to 1000 ppm concentrations.
1.       Name of the student and         Sunita Sen (S-85-A-14-M)
         Admission No.
2.       Name of Major Advisor           Dr. L.N.Bhardwaj
3.       Title of Thesis                 Studies on blight of Solanum laciniatum Ait.
                                         caused by Phytophthora infestans (Mont.) de
                                         Bary
4.       Year of completion of Degree    1987
5.       Abstract of Thesis


        Symptoms of the disease were studied on leaf, flower and fruits including
pathogenicity. Fruits of all ages were found susceptible except the ripe fruits.
Temperature between 25 to 30oC and RH 78 per cent were found vulnerable for leaf
blight and fruit rot development. A positive correlation of the disease was observed with
rainfall, RH and mean minimum temperature and a negative with mean maximum
temperature. Oat meal agar and corn meal agar were found the best medium for
vegetative growth and sporulation. A temperature of 36oC and pH of 6.5 were found
optimum. Ridomil and Dithane M-45 provided significant control of the disease under
field conditions.
1.       Name of the student and          Manoj Kumar Vaid (S-85-A-12-M)
         Admission No.
2.       Name of Major Advisor            Dr. S. V.Bhardwaj
3.       Title of Thesis                  Studies on mosaic disease of broadbean (Vicia
                                          faba L.)
4.       Year of completion of Degree     1988
5.       Abstract of Thesis

        With a view to identify the causal virus of widely occurring mosaic disease of
broadbean, investigations were carried out. Infected plants showed peculiar vein clearing,
severe mosaic of broadbean leading to curling and rolling of leaves in addition to
reduction in their number and size. Virus was transmitted by sap but not by seeds. Virus
was also transmitted by aphid species viz., Myzus persicae, Brevicoryne brassicae and
Aphis fabae. The virus infected members of families leguminosae, chenopopdiaceae,
solanaceae, iridiaceae and compostitae. The virus has TIP between 60-65oC, DEP
1:10,000 to 1:1,00,000 and LIV of 3 days at room temperature and 5 days under
refrigeration. Electron micrographs showed flexuous virus particles of 790x12 nm
diameter. Cytopathological examination showed presence of pin wheels, scrolls, lamellae
tubes as cytoplasmic inclusions. 0.2 M phosphate buffer proved to be the best virus
extracting medium. The virus could be harvested in higher concentration in 6 per cent in
butanol emulsion. All the eight varieties of broadbean screened were highly susceptible
to virus causing mosaic disease under field condition.
1.       Name of the student and           Mange Ram Sinhmar (H-86-19-M)
         Admission No.
2.       Name of Major Advisor             Dr. R.K. Yadava
3.       Title of Thesis                   Exploration of resistance against Alternaria
                                           solani in tomato
4.       Year of completion of Degree      1988
5.       Abstract of Thesis

        Lycopersicon hirsutum f. glabratum (B-6013) remained highly resistant while
Lycopersicon pimpinellifolium (EC-205009) and Lycopersicon peruvianum (EC-148898)
were resistant. The epidermal cell was thickness and cuticle thickness were found more in
resistant species than the susceptible varieties, hence a positive relationship of both the
traits with resistance. The F1’s resulting from resistant x resistant and resistant x
susceptible parents manifested dominance of resistance over susceptibility. The F1 of
susceptible x susceptible, resistant x resistant could not reveal any epistatic interaction.
The resistant species were found to have more total phenols at healthy stage of plants. the
level of total phenols was considerably reduced at severe stage of the disease. The
reduction was found more in susceptible varieties in comparison to resistant species. MS-
101 x Lycopersicon hirsutum f. glabratum (B-6013) had the highest amount of ortho-
dihydroxy phenols at diseased as well as healthy stage whereas Yashwant x Pusa Ruby
depicted the lowest ortho-dihydroxy phenolic quantity. A positive relationship between
ascorbic acid contents and resistance was discernible in both the sets (diallelic and non-
diallelic). Higher amount of total soluble solids at healthy stage were indicative of the
fact that they were of disease inviting nature.
1.       Name of the student and        Sansar Singh Patial (H-86-21-M)
         Admission No.
2.       Name of Major Advisor          Dr. R.D.Sharma
3.       Title of Thesis                Studies on the die back disease of mango
                                        (Mangifera indica L.) in Himachal Pradesh
4.       Year of completion of Degree   1988
5.       Abstract of Thesis

        The average disease incidence in different mango growing districts during the
year 1988 ranged between 13.33 to 55.24 per cent. Die back involves a number of
organisms under Himachal Pradesh conditions viz., Botryodiplodia theobromae,
Pestalotia mangiferae, Colletotrichum gloeosporioides, Fusarium sp., Aspergillus sp.
and Xanthomonas sp. B. theobromae Pat. was found to be a major pathogen associated
with mango die back in Himachal Pradesh. This fungus under our conditions did not
sporulate in culture, however, the pycnidial formation occurred on inoculated twigs.
Among the solid media, potato dextrose agar was best for growth of B. theobromae Pat.
And among the liquid media Richard’s medium was superior to other. Asthana and
Hawker'’ liquid medium was the only medium on which sporulation of the fungus
occurred though vegetative growth was least in this medium. The test fungus can grow
between a range of 15-35oC but 30oC was most optimum temperature. Under field
conditions, Saffeda and Amarpali varieties were resistant to mango die back. Langra and
Dushehri were highly susceptible both under laboratory and field conditions. Three
spraying of captan (0.3%) along with pruning of diseased twigs proved to be superior to
all other treatments.
1.       Name of the student and            Sandeep Kansal (H-86-20-M)
         Admission No.
2.       Name of Major Advisor              Dr. S.S.Bhardwaj
3.       Title of Thesis                    Studies on fungal antagonists of Sclerotinia
                                            sclerotiorum (Lib.) deBary causing stalk rot of
                                            cauliflower
4.       Year of completion of Degree       1988
5.       Abstract of Thesis

        Stalk rot of cauliflower caused by Sclerotinia sclerotiorum (Lib.) deBary is
proving a menace to cauliflower seed crop. The present investigation was carried out to
have the better insight of the nature of antagonism exhibited by associated soil mycoflora
operative against stalk rot pathogen (S. sclerotiorum). The screening of isolated
mycoflora (30 species/isolates) for its antagonism against S. sclerotiorum indicated that
Gliocladium virens and most of the isolates of Trichoderma harzianum and T. viride were
highly efficacious in limiting the sclerotial population in dual culture methods. Similarly
these antagonists were highly efficient in causing the rotting of sclerotia at three different
incubation temperatures. The incubation temperature of 25 or 20oC was found more
suitable than 15oC. G. virens was found highly efficient antagonist as it did not allow the
carpogenic germination of sclerotia at all. G. roseum and isolates of T. harzianum and T.
viride also significantly reduced the carpogenic germination. G. virens and isolates of T.
harzianum and T. viride were efficacious in causing considerable growth inhibition of S.
sclerotiorum by the production of non-volatile toxic substances. The growth inhibition
was recorded more under agar plate culture method than the well method. The lowest
temperature (15oC), proved most suitable than 20 or 25oC for the production of non-
volatile fungitoxic substance. G. deliquescens and isolates of T. harzianum and T.
viride caused considerable growth inhibition of S. sclerotiorum by the production of
volatile toxic substances. Ten days old cultures of antagonists were superior to other ages
in inhibiting the growth of S. sclerotiorum by producing volatile toxic substances.
1.       Name of the student and         Satish Kumar Sharma (H-87-21-M)
         Admission No.
2.       Name of Major Advisor           Dr. N.P.Dohroo
3.       Title of Thesis                 Studies on ginger yellows caused by Fusarium
                                         spp. and its control
4.       Year of completion of Degree    1989
5.       Abstract of Thesis

        The disease appeared in yellow patches in field. Five fusarial species viz.,
Fusarium oxysporum f.sp. zingiberi, F. solani, F. graminearum, F. moniliforme and F.
equiseti were found responsible for ginger yellows in Himachal Pradesh. Morphological
characters of Fusarium spp. were also studied. Potato dextrose agar supported maximum
growth of F. oxysporum f.sp. zingiberi at 25oC. Maximum incidence of yellows (31.33%)
was recorded at 24.6oC and 29.7 per cent temperature and moisture of soil, respectively.
29.3 per cent variation in the disease incidence was due to hydrothermal regimes of soil.
All the varieties/selections were susceptible to the disease. Rhizome dip in Bavistin
(0.1%) for 60 minutes, proved to be an effective measure for the control of ginger
yellows in field and storage. Gliocladium virens managed the disease in storage. Pine
needle and neem cake extracts were equally effective in inhibiting the growth of F.
oxysporum f.sp. zingiberi, in vitro.
1.       Name of the student and          Devinder Kumar Banyal (H-87-21-M)
         Admission No.
2.       Name of Major Advisor            Dr. R.L.Sharma
3.       Title of Thesis                  Studies on grey mould rot of pear caused by
                                          Botrytis cinerea Pers. ex. Fr.
4.       Year of completion of Degree     1990
5.       Abstract of Thesis

        Survey of diseases in fruit markets, stores and collection centres revealed losses
ranging from 2-7 per cent. The diagnostic symptoms of the disease were observed as
firm, pale brown to brown spots on affected fruits which became soft and watery in
advanced stages. The pathogen did not sporulate on host tissue. Surface and stem-end
injuries provided main avenues of penetration. All the pome, stone and vegetable fruit
hosts tested, were susceptible. Potato dextrose agar supported maximum vegetative
growth of the causal pathogen. Among the synthetic media, mycelial growth was
maximum on Richard’s medium at 22oC and pH 5. Pathogen preferred sucrose as carbon
source and sodium nitrate as nitrogen source. It was not found to be deficient in vitamins.
The pathogen did not sporulate in any of the media tested. All the pear cultivars tested
were susceptible to the disease. On the disease development pH had the maximum effect.
Total and OD phenols decreased in the infected fruits. Fruit rot was maximum at 22oC
and minimum at 0oC, while optimum was between 20-25oC. Fungicidal spray did not
affect the qualitative characters of fruit kept in storage. Systemic fungicides namely
Bavistin, Benlate and Martect-50 proved more effective in pre (500 ppm) and post-
harvest (750 ppm) applications then non-systemic (1500, 2000 ppm). Bavistin proved
superior among the fungicides tested.
1.       Name of the student and         Rakhee Chopra (H-88-17-M)
         Admission No.
2.       Name of Major Advisor           Dr. Krishan Kumar
3.       Title of Thesis                 Studies on bacterial blight of pea caused by
                                         Pseudomonas syringae pv. syringae in Himachal
                                         Pradesh
4.       Year of completion of Degree    1990
5.       Abstract of Thesis

        Maximum incidence was observed at Panarasa in Mandi and minimum at Kanda
in Sirmaur. The pathogen survived both in infected plant debris and seed upto next
growing season. Pot house and field experiments clearly indicated that both infected and
infested seeds played an important role in the disease development. The percentage of
disease seedlings and disease index was more in externally and internally inoculated
seeds followed by externally inoculated seeds. Study on the effect of date of sowing
revealed that the disease was more in early as well as late sown crop as compared to
normal date of sowing. The seed-borne inoculum could not be detected by isolation
method. Among different growing on tests viz., traditional, incubation and wounded, the
wounded growing on test proved best for the detection of seed-borne inoculum. In vitro
evaluation of chemicals revealed that Streptocycline was effective at all the
concentrations tested and its efficacy increased with the increase in concentration from
0.01 to 0.05 per cent. There was negligible loss in germination when pea seeds were
soaked for ½ h in tap water, Streptocycline solution (0.01%) and acidic cupric acetate
(0.5%) at 52oC. Among 16 seed treatments tested for the eradication of seed-borne
infection of the bacterium, Streptocycline (0.02%) dip for 3 h was found to be the most
effective.
1.       Name of the student and         Mahender Singh (H-88-15-M)
         Admission No.
2.       Name of Major Advisor           Dr. D.S.Guleria
3.       Title of Thesis                 Nutrient supplementation for Agaricus bitorquis
                                         (Quel.) Sacc. cultivation
4.       Year of completion of Degree    1991
5.       Abstract of Thesis

        When supplementation was done at 0-day of composting, supplements were not
treated with formaldehyde as there was no chance of contamination through
supplementation. Formaldehyde treatment of supplements revealed that 0.3 per cent
concentration of formaldehyde resulted in maximum increase in yield of mushroom and
there was decrease in compost pH with treated supplements as compared to untreated
checks. There was corresponding increase in compost temperature and N content with
supplementation in all the treatment. Maximum increase in compost temperature and N
content was recorded with GNC (2.0%). Compost pH increased in all the supplemented
treatments as compared to control except MC (1.0%) supplementation at spawning. Two
per cent supplementation of compost, irrespective of stage with TC and SBC resulted in
maximum reduction in spawn run and primordial formation duration. Supplementation at
0-day of composting resulted in maximum increase in mushroom yield with 2.0 per cent
supplementation rate of all the supplements. Irrespective of stage and rate of
supplementation, all the supplements resulted in more number of fruit bodies with lighter
weight. Significantly highest yield was recorded when supplementation was done at
casing followed by supplementation both at spawning as well as at casing.
1.       Name of the student and          Anil Kumar Handa (H-89-24-M)
         Admission No.
2.       Name of Major Advisor            Dr. S.V.Bhardwaj
3.       Title of Thesis                  Epidemiology and management of mosaic disease
                                          of broadbean (Vicia faba L.)
4.       Year of completion of Degree     1991
5.       Abstract of Thesis

        The disease incidence was influenced by mean air temperature, relative humidity
and vector population to a greater extent as compared to cumulative rainfall, wind
velocity and total sunshine hours. Medicago denticulata weed found to act as potential
reservoir of the causal virus. Chenopodium amaranticolor subjected to pre-inoculation
treatment of temperature and light developed maximum number of local lesions
showing that the effect of short period of light after the dark period shortly before
inoculation increases susceptibility. The serological studies showed that the present virus
was detectable at a concentration of 1:10,000 for both the reactants (antigen and
antiserum). Virus was detectable by PNC and ALP-based direct antigen coating indirect
ELISA systems at a concentration 1:10,000 for both the reactants. Virus showed very fast
movement within the infected broadbean plant, as it was detectable by ELISA in all the
plant parts within 24 hours of inoculation. Rouging out the diseased plants at seven days
interval showed less incidence of mosaic disease and increased seed yield. Insecticidal
applications with malathion (0.1%) at seven days interval reduced the incidence of
mosaic disease and increased seed yield. The variety Seville Giant was found to be the
best variety because of high tolerance against the disease in addition to high seed yield,
seed weight and pod length.
1.       Name of the student and           Param Vir Yadav (H-88-16-M)
         Admission No.
2.       Name of Major Advisor             Dr. R.C.Sharma
3.       Title of Thesis                   Studies on seed borne fungi of chilgoza (Pinus
                                           gerardiana Wall.) and their effect on seed health
4.       Year of completion of Degree      1992
5.       Abstract of Thesis


        Visual examination of the seed samples revealed that 3.5 per cent seeds were
unfilled and 11.7 per cent had mechanical injuries. Among the seed borne fungi, highest
frequency was that of Penicillium citrinum. Storage temperature had significant effect on
the extent of P. citrinum seed rot. Even storage of inoculated seed at 0 or 5oC did not stop
the decay development. However, shelling percentage, oil content, protein, total sugars,
calcium and phosphorus were higher when inoculated seeds were stored at 0 or 5 oC as
compared to 25oC storage temperature. The seed rot was maximum when inoculated
seeds were stored at 95 per cent relative humidity. Among the five fungicides tested to
check the Penicillium seed rot, carbendazim dip treatment was most effective. Treating
seeds at 60oC for 10 minutes was most effective in checking the Penicillium citrinum
seed decay.
1.       Name of the student and         Narender Kumar (H-90-24-M)
         Admission No.
2.       Name of Major Advisor           Dr. S.K.Sharma
3.       Title of Thesis                 Persistence of carbendazim and mancozeb on
                                         apple foliage and fruits
4.       Year of completion of Degree    1993
5.       Abstract of Thesis

        Persistence of carbendazim @ 0.05 per cent on apple fruits was upto 35 days and
on leaves upto 35 days in one and two sprays and 45 days in three and four sprays when
analyzed spectrophotometrically. RL50 for fruits was 14-18 and 10-21 days on leaves. Per
cent dissipation was maximum in one spray and residues were below MRL. RL50 and
waiting period was maximum in four sprays. In bioasay studies, carbendazim was found
to persist for 10 days on fruit sand for 15 days on leaves. Mancozeb (0.3%) by
spectrophotometric method was detected upto 25 and 35 days in apple fruits and eaves,
respectively. Waiting period for fruits and leaves ranged between 8-9 days and 32.36
days and RL50 between 3-4 and 5-6 days, respectively. In bioassay, mancozeb was
found to persist upto 7 days in fruits and 10 days in leaves. Persistence of carbendazim
and mancozeb was enhanced upto 45 days by addition of stickers on leaves while there
was no effect of stickers on fruits. Dissipation of carbendazim and mancozeb was faster
on the upper plant portion as compared to lower one. In storage, carbendazim was found
to persist upto 30, 60, 60 and 60 days at ambient temperature and 120, 180, 180 and 180
days at low temperature (0-20oC) in the dip treatments at 250, 500, 750 and 100 ppm,
respectively, when analyzed spectrophotometrically. The waiting period was calculated
to be2.40, 5.22 and 7.84 days at ambient temperature and 12.45, 28.45 and 44.35 days at
low temperature in the dip treatments at 500, 750 and 1000 ppm, respectively. The
fungicide concentration was below tolerance level of 5 ppm at a dip treatment of 250
ppm. RL50 was approximately 12 days at ambient temperature and 60-67 days in the
fruits kept at low temperature indifferent concentrations.
1.       Name of the student and          Push Deep Sharma (H-90-24-M)
         Admission No.
2.       Name of Major Advisor            Dr. T.R.Shandilya
3.       Title of Thesis                  Recycling of spent compost for cultivation of
                                          white button mushroom (Agaricus bisporus
                                          (Lange) Imbach)
4.       Year of completion of Degree     1993
5.       Abstract of Thesis

        Increase in the nitrogen percentage from the day of spawning to +28th day of
cropping ranged between 0.08 to 0.28, 0.04 to 0.23 and 0.08to 0.24 per cent in various
combination ratios of spent compost + wheat straw, spent compost + ready compost and
in the control treatment (unsupplemented and supplemented spent compost, standard
compost treatments), respectively. The pH level showed an intermittent decrease with the
progression of cropping (from day of spawning till the end of harvesting). The range of
decrease in pH levels during the cropping was 0.6 – 0.8 in all the combinations. Moisture
content, alike pH level, exhibited gradual and intermittent decrease from spawning till the
end of picking. In different combination ratios of spent compost + wheat straw and spent
compost + ready compost the range of decrease in moisture percentage during cropping
progression was between 2.0 – 3.5 and 2.0 - 4.0 per cent. It was observed that in 1:9, 2:8,
3:7, 4:6, 5:5 ratios of spent compost + wheat straw, the temperature range of 0 day of
composting was 49-50oC which reached maximum level of 70.0 – 71.5oC at +6 day of
composting. The spent ammonia concentration in 1:9, 2:8, 3:7, 4:6 combination ratios of
spent compost + wheat straw and in standard compost was >700 ppm from 0 day to +4
day of composting. Standard compost gave the highest yield (465.00 g/week/15 kg
compost) as compared to all other combination treatments under study. On economic
studies, 5:5 combination ratio of spent compost + wheat straw gave the maximum cost
benefit ratio (1:2:53). Various moulds (olive green, black whisker and caps and sciarid
flies were found infesting the cropping.
1.       Name of the student and         Deepak Kumar Gupta (H-91-3-M)
         Admission No.
2.       Name of Major Advisor           Dr. Madhu Meeta
3.       Title of Thesis                 Studies on stem rot of carnation (Dianthus
                                         caryophyllus L.)
4.       Year of completion of Degree    1994
5.       Abstract of Thesis

        Stem rot of carnation caused by Rhizoctonia solani is a serious menace to the
carnation cultivation in Himachal Pradesh. The symptoms of stem rot are manifested as
rotting of under-ground stem portion, chlorosis, wilting and drying of leaves. The fungus
requires 30oC temperature and 60-80 percent moisture level for its optimum growth and
development. William Sim and Vermillion Protruding cvs. of carnation were found to be
resistant of stem rot. Amongst the various antagonists tested against R. solani and
Trichoderma viride gave the maximum inhibition of the test fungus. The fungus was
successfully controlled by the application of Bavistin, Contaf and Rubigan under in vitro
conditions while under pot conditions, drenching by Punch, Captan and Dithane M-45
proved to be more successful in disease management.
1.       Name of the student and          Yussouf Khan (H-91-33-M)
         Admission No.
2.       Name of Major Advisor            Dr. R.C.Sharma
3.       Title of Thesis                  Studies on Melampsora leaf rust of Populus
                                          species
4.       Year of completion of Degree     1994
5.       Abstract of Thesis

        The disease was first recorded at Nauni on grown up trees of Populus deltoides
‘Lux’ in the month of April. In the nursery, the disease first appeared on P. ciliata
seedlings in June. At Palampur and Bajaura nurseries, disease was first observed in
August. Disease did not appear in Nalagarh nursery, Disease leaf fall and apparent
infection rate was maximum in P. nigra x trichocarpa, while AUDPC and leaf fall were
minimum in P. yunnanensis. Urediniospore production per uredinium was maximum in
P. nigra x trichocarpa, while it was least in P. ‘Oxford’. Disease appeared to months late
in the new nursery site as compared to old nursery site. At two week interval post-
symptom cyperoconazole spray was best in checking the disease.
1.       Name of the student and           Dharmesh Gupta (H-92-22-M)
         Admission No.
2.       Name of Major Advisor             Dr. P.D.Thakur
3.       Title of Thesis                   Studies on a viral disease of tomato
                                           (Lycopersicon esculentum Mill.)in Himachal
                                           Pradesh
4.       Year of completion of Degree      1995
5.       Abstract of Thesis

        The viral nature of the pathogen was proved by serial mechanical transmission
tests. Investigations were carried out on symptomatology, host range, transmission
(through sap, aphids and seed), biophysical properties, particle morphology and serology
to identify the virus. Different varieties of tomato (Lycopersicon esculentum Mill.) were
also screened to find out the source of resistance against the virus. The incidence of virus
disease(s) of tomato reported, varied from 5.0 to 100 per cent in different localities of
Solan. Characteristic symptoms produced by the virus on tomato included vein clearing,
mild mosaic, downward rolling of leaves and reduction in size of leaves. Infected plants
were stunted in growth and produced lesser number of small sized fruits. The virus was
transmitted by the aphid species viz., Myzus persicae, Aphis craccivora, A. gossypii. The
host range of the virus was restricted to a few solanaceous hosts only. In addition to
tomato varieties, the virus infected Capsicum annuum, Datura metel and D. metel var.
fastuosa only. The biophysical properties of the virus included thermal inactivation point
(TIP) between 50-55oC, dilution end point (DEP) between 1:1000 to 1:10,000 and
longevity in vitro (LIV) of 72 hours at room temperature (24-29oC) and 120 hours at
refrigerated temperature (5±1oC). the present virus was not serologically related to eight
antisera tested viz., PVYo, PVA, TEV, BCMV, PMV, AzPV and PVMV, all belonging to
potyvirus group. Electron microscopic studies revealed the presence of flexuous rod
shaped particles (740 x 12 nm) typical of the potyvirus group. Cytopatological studies
showed pinwheels, scrolls and laminated aggregates in tomato leaf tissue infected by the
virus. Based on different identification criteria particularly, the particle morphology,
cytopathology and serological relationship, the virus was identified as a distinct one not
related to any other virus of the potyvirus group so for reported on the host.
1.       Name of the student and          K. Abraham Mathew (H-93-18-M)
         Admission No.
2.       Name of Major Advisor            Dr. S.K.Gupta
3.       Title of Thesis                  Studies on root rot and web blight of French bean
                                          (Phaseolus vulgaris L.) caused by Rhizoctonia
                                          solani Kuhn.
4.       Year of completion of Degree     1995
5.       Abstract of Thesis

        French bean (Phaseolus vulgaris L.) was severely affected by root rot and web
blight (Rhizoctonia solani Kuhn) during 1994 crop season and this disease was found to
be more severe in bush type as compared to pole type cultivars of this crop. High rainfall,
soil moisture and relative humidity coupled with soil temperature (23-25oC) were found
to favour the disease (web blight) development. These studies also revealed that all the
tested cultivars irrespective of seed colour were susceptible to the disease. Bavistin seed
treatment significantly reduced the severity of web blight under glasshouse conditions.
Soil drenching with Bavistin also provided excellent control of the disease. Under field
conditions seed treatment with Celest (0.2%), Raxil (0.25) and Bavistin (0.2%) followed
by foliar sprays of Bavistin (0.05%) was highly effective and was closely followed by
Topsin-M and Baycor. Celest (ST) and Bavistin (FS) gave maximum green pod yield
while Bavistin provided maximum seed/pod yield. Among the soil amendments,
application of sawdust and wheat straw proved quite effective in containing the pre-
emergence root rot while sunflower cake was effective against post-emergence root rot.
Among the various antagonistic tested, application of Trichoderma harzianum was found
effective in reducing both pre- and post emergence root rot.
1.       Name of the student and         Bhupesh Kumar (H-94-24-M)
         Admission No.
2.       Name of Major Advisor           Dr. M.K.Behl
3.       Title of Thesis                 Studies on inhibition of mosaic virus in tomato
                                         plants by plant extracts
4.       Year of completion of Degree    1996
5.       Abstract of Thesis

        The investigations were undertaken to study tobacco mosaic virus inhibition with
plant extracts. MS medium was also standardized for callous induction, shoot and root
regeneration of tomato cv. Solan Gola. Extracts used were cold water fraction of
Mirabilis jalapa roots, acetone fraction of Asparagus adscendens roots, alcohol fraction
of Vitex negundo leaves, and cold water fraction of Symphytam perigrinum roots. These
fraction were evaluated at different concentrations and most effective inhibitors were
Vitex negundo leaves @ 7 ppm, Asparagus adscendes roots @ 1 ppm, Mirabilis jalapa @
3 ppm and Symphytum perigrinum roots @ 10 ppm against tobacco mosaic disease virus.
While daily sprays with cold water fraction of M. jalapa roots at 1 ppm concentration in
pre- and post-inoculation treatment, respectively gave maximum inhibition of the virus.
In tissue culture studies. MS medium supplemented with 3 mg 1-1 BAP and 1 mg 1-1
NAA, resulted into production of good callus. Shooting was obtained best in medium
supplemented with 5.0 mg 1-1, BAP and 0.1 mg 1-1 IAA, and rooting with 0.1 mg 1-1
NAA. Medium supplemented with various plant extracts resulted in reduction of virus
concentration in callus tissues. Out of different plant extracts, acetone fraction of
Asparagus adscendens resulted in maximum per cent reduction (94.19) in the
concentration of the virus in callus tissues.
1.       Name of the student and         Sanjeev Kumar (H-94-27-M)
         Admission No.
2.       Name of Major Advisor           Dr. N.P.Dohroo
3.       Title of Thesis                 The      influence of    vesicular-arbuscular
                                         mycorrhizae on incidence of ginger yellows
                                         caused by Fusarium oxysporum f.sp. zingiberi
                                         Trujillo
4.       Year of completion of Degree    1996
5.       Abstract of Thesis

        Yellows of ginger caused by Fusarium oxysporum f.sp. zingiberi Trujillo is one
of the destructive diseases in Himachal Pradesh. The VAM fungi associated with ginger
soils were identified and their morphological characters were described. A definite
relationship between chlamydospore number of VAM fungi and disease incidence was
found. The root colonization was maximum in Trichoderma harzianum, T. harzianum +
Glomus mosseae and T. harzianum + Acaulospora laevis treatments when applied in
pine needle amended soil. The seed treatment of T. harzianum and soil application of
either Gigaspora morgarita or G. mosseae resulted in maximum yield of ginger
rhizomes. T. morgarita increased dry weight, mycorrhizal inoculation efficiency and
phosphorus contents of ginger plants. A definite relationship of soil hydrothermal
regimes with the disease development and population of VAM fungi was investigated.
Incorporation of organic amendments increased the spore number of VAM fungi and
decreased the disease incidence. Farm yard manure + straw grass and pine needles
yielded maximum number of chlamydospores with minimum incidence of the disease.
Intercropping of chilli decreased the incidence of yellows. Pine needle amendment alone
and in combination with fungicide seed treatment i.e., Indofil M-45 (0.25%) + Bavistin
(0.1%) for 60 minutes resulted in maximum seed germination. Similarly, the soil organic
amendment in combination with fungicide seed treatment or T. harzianum seed treatment
+ G. margarita soil application decreased incidence of yellows and increased the yield of
ginger.
1.       Name of the student and           Arti Shukla (H-94-23-M)
         Admission No.
2.       Name of Major Advisor             Dr. R.L.Sharma
3.       Title of Thesis                   Studies on postharvest soft rot of bell pepper
                                           caused by Fusarium sp.
4.       Year of completion of Degree      1997
5.       Abstract of Thesis

        Bell pepper fruits are highly susceptible to soft rot caused by Fusarium equiseti
(Corda) Sacc. and F. semitectum Berk and Rav. Especially in South Africa and India.
Survey of vegetable markets, stores and collection centres revealed 2.8 to 9.6 per cent
losses. The symptomatology of the disease and morphological characters of the pathogen
were described. Both the species exhibited almost similar symptoms although F.
semitectum was more virulent than F. equiseti. Injured surface and stem end (intact)
provided main avenues of penetration for the test pathogens. Among the different
varieties/hybrids screened, hybrid Bharat was found to be moderately resistant and stone
fruit tested were infected by Fusarium spp. Storing bell pepper between 5-10oC was
found the most suitable temperature range for checking soft rot infection. Potato dextrose
agar and Richards’ agar were the best media for growth and sporulation of fungi.
Optimum temperature for the growth of F. equiseti and F. semitectum was 30 and 25oC,
respectively. Maximum growth and sporulation was obtained at pH 6 and 6.5 for F.
equiseti and F. semitectum, respectively. The test fungi preferred sucrose as the best
source of carbon and potassium nitrate was found the best nitrogen source. Bavistin and
Benlate among the systemic fungicides and Ridomil –MZ and Captaf among the non-
systemic were effective in vitro. Preharvest spray of Bordeaux mixture and Bavistin
proved highly effective. Among the non-systemics Ridomil-MZ gave the highest control.
Fruits packed in wooden boxes with iodine and diphenylamine impregnated liners
reduced the soft rot infection considerably. Post-harvest dip treatment of fruits in Bavistin
and Benlate provided maximum disease control. among the non-systemics Ridomil MZ
and diphenylamine at 2000 ppm concentration were promising.
1.       Name of the student and           Deepika Sood (H-95-21-M)
         Admission No.
2.       Name of Major Advisor             Dr. J.L.Kaul
3.       Title of Thesis                   Toximetric studies of Botran against Rhizopus
                                           stolonifer causing whisker’s rot of peaches
4.       Year of completion of Degree      1997
5.       Abstract of Thesis

         In vitro screening of Botran against Rhizopus stolonifer revealed that 5 ppm
concentration was most effective resulting in 95.27 per cent inhibition of mycelial
growth. The maximum per cent spore germination inhibition was recorded with 50 ppm.
The maximum (94.99%) inhibition of germtube length was recorded at 9 ppm. In vivo
evaluation of various fungitoxicants are preharvest sprays revealed that Botran was the
most effective as compared to other fungitoxicants (Bavistin, Indofil M-45) used. The
postharvest Botran dip treatments proved effective both as protectant (pre-inoculation)
and eradicant (post-inoculation). Botran was found to be the most efficacious under both
the stages at 1500 ppm. There was decrease in efficacy of Botran with decrease in its
concentration irrespective of pre-or post-inoculation treatments. There was significant
reduction in total phenols in diseased tissue as compared to inoculated healthy or
uninoculated peach fruit tissue. Botran at 750 ppm significantly checked the reduction in
total phenols as compared to other test concentrations. Similarly, the activity of both
macerating enzymes (polygalactduronase and cellulase) was found to be highest in
diseased tissue as compared to healthy uninoculated and inoculated tissues. The enzyme
activity was less in Botran treated fruits as compared to untreated control, and 750 ppm
was found to be more effective as compared to lower concentration in retarding the
enzyme activity. The contents of total and reducing sugars were found to be significantly
more in uninoculated tissue followed by inoculate healthy tissue as compared to disease
tissue which registered minimum level of total and reducing sugars. Higher
concentrations of Botran (750 ppm) treatment resulted in maximum retention of total and
reducing sugar with corresponding decrease in contents at lower concentrations (500 and
350 ppm). As with other biochemical parameters, higher concentrations of Botran
resulted in retention of higher levels of TSS and titratable activity. The shelf of peach
fruits revealed that inoculation with R. stolonifer resulted in reduction of TSS, titratable
acidity, total and reducing sugars as well as fruit firmness. The higher concentrations of
Botran (750 ppm) resulted in retention of more contents and firmness as compared to
lower test concentrations. There was no disease development at 5 or 10oC. However,
storage at ambient temperature (30±1oC) resulted in remarkable reduction of various
constituents analyzed. Storage for two days did not cause any appreciable change in the
contents of various constituents as well as firmness whereas sharp decline occurred in
these constituents with corresponding increase in storage period from 2 to 8 days.
1.       Name of the student and          Mamta Sharma (H-94-25-M)
         Admission No.
2.       Name of Major Advisor            Dr. D.S.Guleria
3.       Title of Thesis                  Effect of different casing materials on the yield
                                          and quality parameters of Agaricus bitorquis
                                          (Quel.) Sacc.
4.       Year of completion of Degree     1997
5.       Abstract of Thesis

        Among various casing materials tested in the present study, two years
decomposed FYM + loam soil in 1:1 (v/v) ratio resulted in maximum mushroom yield
(14.45 kg/q compost. Addition of either 100 ml or 150 ml water to casing material per
day either in single application or double application resulted in higher yield as compared
to other treatments and the difference between two were statistically non-significant.
Drenching of casing soil with 2 per cent formaldehyde followed by its storage at 30oCfor
15 days resulted in 13.95 kg/q compost mushroom yield which was statistically at par
with the yield recorded in steam pasteurized casing material. Among the various
fungicides sprayed in the casing soil, Bavistin (0.1%) resulted in minimum number of
fungal colonies and produced maximum (17.35 kg/ q compost) yield of A. bitorquis.
Dimilin (0.25%) proved the best insecticides among all the tested one as it could keep the
crop free from sciarid as well as phorid flies and resulted in maximum production of
mushroom (17.55 kg/q compost). Application of spawned casing induced early pinning
(15-18 days) as compare to control (22-24 days). The yield of mushroom was 19 and
19.25 kg/q compost with addition of 0.10 per cent grain spawn and 1,5 per cent of spawn
compost to casing as compare to 16.50 and 16.25 kg/q compost in respective controls`.
1.       Name of the student and          Pradeep Sharma (H-95-27-M)
         Admission No.
2.       Name of Major Advisor            Dr. P.D.Thakur
3.       Title of Thesis                  Studies on a streak mosaic in sweet peas
                                          (Lathyrus odoratus L.)
4.       Year of completion of Degree     1997
5.       Abstract of Thesis

        The characteristics symptoms produced by the virus on sweet pea included flecks,
cupping of infected leaves, chlorotic streaks and necrosis of the whole leaf lamina.
Flowering was delayed and flowers so produced exhibited colour breaking symptoms.
The virus was easily transmitted through sap and aphid vectors viz., Acyrthesiphon
pisum, Myzus persicae, Aphis fabae, Brevicoryne brassicae, but not through seeds of
infected plants. The virus was found to infect a few members of the families viz.,
fabaceae, chenopodiceae and solanaceae. The virus had TIP of 55-60oC, DEP ranged
between 1:1000 to 1:10,000 and LIV was 3 day at room temperature and 5 days at
freezing temperature (5±1oC). Electron microscopic studies revealed the presence of
flexuous rod shaped particles (750x12 nm) typical of the potyviruses. Based on different
identification parameters, the virus was identified as a member of potyviridae family and
tentatively designated as sweet pea streak mosaic (?) potyvirus. Twenty lines/varieties of
sweet pea tested for the infection by the virus, showed varying degree of susceptibility,
except Pocha seed, which was found to be resistant under field conditions.
1.       Name of the student and           Meenu Gupta (H-96-26-M)
         Admission No.
2.       Name of Major Advisor             Dr. R.C.Garg
3.       Title of Thesis                   Studies on ripe fruit rot of chilli caused due to
                                           Colletotrichum capsici (Syd.) Butler and Bisby
4.       Year of completion of Degree      1997
5.       Abstract of Thesis

         The ripe fruit rot caused due to Colletotrichum capsici was present in all the
localities. Pathogenicity was proved on immature green, mature green and ripe red chilli
fruits where fruits after inoculation were covered with moist alkathene bags upto nine
days . Characteristic symptoms of the disease were exhibited as dark yellowish to brown,
slightly sunken spots on fruit surface which later turned greyish and became studded with
acervuli of the fungus giving a target board appearance. Infected seeds were rusty and
shrivelled in appearance. Morphological characters of the fungus were also studied, shape
and size of acervulus, setae, conidiophores and conidia were recorded. High rainfall
coupled with high relative humidity favoured the development of ripe fruit rot. Richards
medium was found to be the best as basal medium for growth of C. capasici. It preferred
28oC temperature for maximum growth and the fungus grew best at 5.5 pH and 92 per
cent relative humidity. C. capasici was found to be seed transmitted to the extent of
32.77 per cent in chilli fruits when tested by agar plate method. Three cultivars/lines viz.,
Perennial Solan Selection –I and Hungarian Wax were observed to be moderately
susceptible to C. capasici. Bavistin, Punch and Aureofungin among systemics and
Indofil M-45 and Celest among non-systemics were most effective in inhibiting mycelial
growth of the fungus. In field trials, seed treatment with Bavistin, Contaf, Topsin-M and
Baycor and foliar sprays of Bavistin, IndofilM-45, Baycor, Topsin-M, Contaf and Punch
proved most effective. Application of Bavistin resulted in maximum yield of ripe fruits.
1.       Name of the student and           Shalini Verma (H-95-29-M)
         Admission No.
2.       Name of Major Advisor             Dr. K.R.Shyam
3.       Title of Thesis                   Epidemiology and management of leaf blight and
                                           fruit rot of bell pepper
4.       Year of completion of Degree      1997
5.       Abstract of Thesis

        Phytophthora nicotianae var. nicotianae was invariably found to be associated
with the symptoms produced on leaves, fruits and stems whereas P. capsici could be
isolated from the two samples only. P. n. var. nicotianae was found pathogenic on
fourteen host belonging to families solanaceae, leguminosae and cucurbitaceae and was
non-pathogenic to Solanum capsicastrum with incubation period ranging from 8 to 84 h
minimum on Datura stramonium. Among the fourteen solid media tried, maximum
mycelial growth was observed on rice meal agar (90 mm) while sporangial production
was observed on onion bulb agar and cucumber fruit agar. The sporangial germination
was found maximum in rain water (87.61%). With the increase in leaf wetness period
from 4 to 24 h a progressive decrease in incubation periods from 49 to 28 and 52 to 31 h
were recorded for leaves and fruits, respectively. At highest RH (100%), the incubation
period was shortest (28h). At 25oC temperature, the incubation period was shortest (28 h).
The simple correlation coefficients of soil moisture with leaf blight severity and fruit rot
incidence were found to be positive and highly significant (0.7938 and 0.6494). The
multiple correlation coefficient revealed that 84.58 and 70.28 per cent changes in the leaf
blight severity and fruit rot incidence, respectively, were caused by soil moisture and soil
temperature. Out of 29 cvs./lines screened against . P. n. var. nicotianae, only Kandaghat
Selection was found resistant which remained disease free. Among the various treatments
of pine needle mulch alone and in combination with sprays of Blitox –50 and Ridomil
MZ, Ridomil MZ on pine needle mulch and foliage was most efficacious in controlling
the disease.
1.       Name of the student and          Vijay Kumar Thakur (H-95-31-M)
         Admission No.
2.       Name of Major Advisor            Dr. C.L.Jandaik
3.       Title of Thesis                  Occurrence of weed fungi and their management
                                          during cultivation of Pleurotus cajor-caju (Fr.)
                                          Singer.
4.       Year of completion of Degree     1997
5.       Abstract of Thesis

        Amongst various weed fungi (Trichoderma viride, T. harzianum, Trichothecium
roseum, Chaetomium globosum and Gliocladium species) encountered during the survey
of different Pleurotus growing units located at different locations in Himachal Pradesh
(Shimla, Solan, Kandaghat, Dharot), it was found that the frequency and incidence of T.
viride was maximum followed by T. harzianum and Trichothecium roseum. In paired
cultured studies (both radial and diametric), all the weed fungi inhibited the growth of P.
sajor-caju considerably. The culture filtrates of weed fungi when evaluated either by
Well or Cellophane method established production of metabolites antagonistic of P.
sajor-caju. The different weed fungi studied were not found to produce volatile
metabolites as there was less than 8 per cent inhibition in growth of P. sajor-caju in all
the cases even after 72 hours of inoculation. All the weed fungi studied were easily
managed by the use of Bavistin and Kribenomyl (0.05%). Two sprays first at spawning
and second at weed fungi inoculation stage resulted in higher yield as compared to single
spray application at the time of spawning irrespective of fungicides. Amendment of straw
with various plant extracts (neem cake, pine needles, water hyacinth and eucalyptus
leaves) @ 5 kg/100kg dry straw resulted in enhanced yield of mushroom fruit bodies
irrespective of weed fungus inoculation.
1.       Name of the student and          Amita Gupta (H-95-20-M)
         Admission No.
2.       Name of Major Advisor            Dr. S.K.Gupta
3.       Title of Thesis                  Studies   on powdery mildew of cucumber
                                          (Cucumis sativus L.)
4.       Year of completion of Degree     1998
5.       Abstract of Thesis

        Powdery mildew disease of cucumber (Cucumis sativus L.) appear in moderate to
severe form in Solan and surrounding areas. On the basis of presence of typical
anamorphs of the pathogen like ectophytic mycelium, unbranched conidiophores with
cylindrical foot cell, ellipsoidal conidia arranged in long chains in basipetal succession,
presence of fibrosin bodies in conidium, simple/forked germtubes and absence of
appresorial formation by conidium of the pathogen, the fungus was identified as
Sphaerotheca fuliginea (Schlecht.) Poll. The incubation and latent period of the pathogen
was shorter on cotyledonary leaves than first true leaves. S. fuliginea was found to be
pathogenic on cucurbitaceae plants except Luffa cylindrica and Momordica charantia.
The conidial germination was maximum at 25oC temperature and 100 per cent RH. The
relative humidity, rainfall, mean air temperature and sunshine hours considerably
influenced the powdery mildew development. Lines viz., GYN-1, Sel. 75-1-10, EC
173934, Sel. 75-1-10, DCH-1, Solan KH-1 and DCH-2 were observed to be moderately
resistant. Among various fungitoxciants tested, Bavistin (50 ppm) and Karathane (100
ppm) completely checked the conidial germination. Among EBI fungicides, Topas (10
µg/ml) and Contaf (50 µg/ml) caused maximum inhibition of germtube length. Punch
(0.04%) and Contaf (0.05%) exhibited maximum antisporulant activity i.e. upto 10 days.
Maximum disease control and fruit yield were provided by spray applications of Contaf
(0.05%) and Bavistin (0.05%), respectively
1.       Name of the student and         Kumud Verma (H-95-24-M)
         Admission No.
2.       Name of Major Advisor           Dr. R.C.Sharma
3.       Title of Thesis                 Studies on epidemiology and management of
                                         powdery mildew of peas
4.       Year of completion of Degree    1998
5.       Abstract of Thesis

        Disease severity was maximum in late October (26.10.96) sown crop and least in
late November sown (26.1.96) crop. Among the three varieties, disease was maximum in
VL-3 in all dates of sowing. Apparent infection rate was maximum in early November
(06.11.96) sown crop and least in late November sown crop, while AUDPC was
maximum in late October sown crop and minimum in late November sown crop. Mean
pod number per plant were maximum in early November sown crop and in varieties VL-3
and Bonneville, while mean yield per plot was maximum in late October sown crop and
variety VL-3. A positive and significant correlation (simple) or positive (partial and
multiple) and non-significant correlation between relative humidity and disease incidence
indicated that disease development was influenced by temperature. Plant characters like
pod length, shoot length, root length, nodulation and yield parameters like pod number
per plant, peas per pod, shelling percentage and pod yield showed a significant reduction
due to disease. Out of 105 pea germplasm lines screened for resistance, 38 were classed
as highly resistant, 3 resistant, 12 moderately resistant, 30 susceptible and 22 highly
susceptible. Sulfex (0.2%) sprayed at 15 days intervals gave the best control. On an
average Bayleton (0.05%) was proved to be the best fungicide to control the disease and
Kribenomyl was least effective.
1.       Name of the student and         Rajinder Singh Jarial (H-95-28-M)
         Admission No.
2.       Name of Major Advisor           Dr. V.P.Sharma
3.       Title of Thesis                 Studies on false truffle (Diehliomyces
                                         microsporus) of Agaricus spp. and its
                                         management
4.       Year of completion of Degree    1998
5.       Abstract of Thesis

        The frequency and increase of false truffle varied between 0-3 and 0-37 per cent,
respectively in different units. MEA medium was found to the best for mycelial growth
and very good for ascocarp production of Diehliomyces microsporus. A temperature of
26oC and 6.0 pH, were found to be the best as these supported maximum mycelial growth
and ascocarp production. Starch and sodium nitrate were found to be the best carbon and
nitrogen sources, respectively as they supported the maximum mycelial growth. Among 5
trace-elements, zinc sulphate was found to be the best, as it supported good growth of D.
microsporus. In the paired culture studies (both radial and diametric), D. microsporus
inhibited growth of Agaricus spp. considerably. The cultural filtrate of D. microsporus
when evaluated either by Well or Cellophane methods, established production of
metabolites antagonistic to the growth of Agaricus spp. Different fungicides namely,
Benlate, Bavistin, Topsin-M and Indofil M-45 resulted in cent per cent inhibition of D.
microsporus under in vitro conditions. A spray schedule consisting of three fungicides
(Bavistin, Benlate and Topsin-M) was quite effective in managing false truffle.
Amendments of compost with 3 per cent (w/w) water hyacinth resulted in considerable
reduction in false truffle incidence and enhanced yield of mushroom fruit bodies.
1.       Name of the student and           Dharmender Mehta (H-95-22-M)
         Admission No.
2.       Name of Major Advisor             Dr. S.Kumar
3.       Title of Thesis                   Evaluation of tissue and spore culture in spawn
                                           production of Agaricus bisporus (Lange) Imbach.
4.       Year of completion of Degree      1998
5.       Abstract of Thesis

        Among various tissue culture isolates and multispore cultures raised from
mushroom fruit bodies, tissue cultures raised from pileus showed the maximum diametric
growth. Evaluation of different culture media revealed that compost extract agar medium
was the best to support maximum diametric growth and desirable growth type. In
compost, cultures raised from pileus outer (Po) showed the faster downward mycelial
growth rate and all the cultures showed the strandy type of growth. Among various grains
used for spawn production, jowar grains were the best to support maximum downward
mycelial growth, significantly higher yield and desirable morphological characteristics
(average fruit body weight, toughness, colour, smoothness and shape) for all the culture
isolates. The overall yield of pileus culture isolates was higher than that of stipe and the
culture raised from the junction of stipe and pileus. Among pileus cultures, culture
isolated from pileus centre (Pc) was the highest yielded with fruit bodies having most
desirable morphological characters. Regarding the morphological variation for stipe
length, stipe diameter and pileus diameter cultures isolated from pileus middle and stipe
base exhibited minimum and maximum variation, respectively.
1.       Name of the student and         Ruchi Sood (H-96-22-M)
         Admission No.
2.       Name of Major Advisor           Dr. R.L.Sharma
3.       Title of Thesis                 Studies on postharvest rot of tomato caused by
                                         Alternaria species
4.       Year of completion of Degree    1998
5.       Abstract of Thesis

         Tomatoes are highly susceptible to fruit rot caused by Alternaria spp. In
Himachal Pradesh, the disease is on increase and 4.81 to 11.75 per cent losses were
recorded during survey of various vegetable markets. The three Alternaria spp. viz., A.
alternata, A. solani and A. tomato were differentiated on the basis of pathological,
morphological and cultural characteristics. Alternaria spp. caused maximum infection
through the injured surface and stem end (removed). None of the varieties/hybrid tested
was completely resistant to Alternaria spp. Among the synthetic media, Richard’s
solution supported maximum growth of the test fungi and therefore, selected as a basal
medium for conducting physiological studies. Maximum growth of test fungi was
observed at 30oC and 6.0 pH. Fruit rot could be checked by storing the tomatoes between
5-10oC. Alternaria spp. causing fruit rot of tomato were completely checked when
inoculated fruits were exposed to heat treatment at 38oC for 96 hours, followed by
storage at 20oC for 12 days. Hot water treatment of tomatoes at 52oC effectively checked
the infection. Hot water supplemented with mancozeb (500 ppm) further enhanced the
efficacy of the treatment. A single preharvest application of Indofil M-45 given one week
before the expected date of picking of tomatoes significantly reduced infections by
Alternaria spp. during the storage. Five minutes postharvest dip treatment of tomatoes
with non-systemics fungicides viz., Captan, Ridomil –MZ or Indofil M-45 were
efficacious than the systemic viz., Bavistin in both pre-inoculation and post-inoculation
test series.
1.       Name of the student and         Hans Raj Negi (H-96-18-M)
         Admission No.
2.       Name of Major Advisor           Dr. N.P.Dohroo
3.       Title of Thesis                 Studies on storage rot of seed ginger (Zingiber
                                         officinale Rosc.)
4.       Year of completion of Degree    1998
5.       Abstract of Thesis

        The present investigations were carried out during the years 1996-97 and 1997-
98. The losses due to storage rots ranged from 1.5 to 60 per cent in Himachal Pradesh.
Seven fungi associated with storage rots of ginger were identified. The pathogenicity
tests as well as the morphological characters of three predominant fungi were described.
A definite relationship of storage temperature and relative humidity with storage rots of
seed ginger was investigated. The role of harvesting time on the storage rots was also
studied. The rhizome curing for 48 and 60 hours was found most effective in reducing the
rhizome weight, the disease incidence and increasing the rhizome recovery. Pre-storage
treatment of Topsin- M (0.2%) and Bavistin (0.2%) was found most efficacious, in
reducing the loss in rhizome weight, disease incidence and increasing the rhizome
recovery. It was also found to increase the emergence and yield of ginger in field. Pre-
storage treatment of NAA and MH in combination with Dithane M-45 + Bavistin
checked shrivelling and sprouting of rhizomes during storage in pits.
1.       Name of the student and            Manica Tomar (H-95-25-M)
         Admission No.
2.       Name of Major Advisor              Dr. V.K.Gupta
3.       Title of Thesis                    Studies on the management of gladiolus yellows
                                            caused by Fusarium species
4.       Year of completion of Degree       1998
5.       Abstract of Thesis

        During the course of present investigations (1996-97), different aspects of
gladiolus growing areas of HP revealed that the disease incidence was more in warmer
areas than that of cooler areas. Two species of Fusarium i.e. Fusarium oxysporum f.sp.
gladioli and F. monoliforme were found carrying wilt of gladiolus in the state. However,
the detailed investigations were carried out in case of F.o. f.sp. gladioli as it was found to
be more virulent than F. monoliforme. The symptomatology of the disease was studied in
detail. The role of edaphic factors such as soil temperature, soil pH, soil moisture and soil
type were studied in depth on the disease development. The temperature of 27-33oC,
available soil moisture of 60 per cent and pH of 6.5 and loam and sandy loam soils were
found to be the controlling factor in the disease initiation and development. Experiments
of disease management were carried out both in storage and field. Best management of
storage rot was achieved when corms were stored in cloth bags followed by metal trays
and paper bags. Amongst various chemicals fungicides use of mercuric chloride, Kavach
and Bavistin gave significantly superior control of rot in storage over untreated corms.
Bavistin and Dithane M-45 gave best control of wilt under field conditions. Hot water
treatment at 56oC for 30 minutes was found highly effective in reducing the disease
incidence. In case of organic amendments, soil amended with neem cake followed by
mustard cake were found effective against yellows. Out of forty varieties only few like
Yellow Supreme, Apollo were found resistant to F.o. f.sp. gladili under field conditions.
1.       Name of the student and           Nirupma Kumari Nag (H-95-23-M)
         Admission No.
2.       Name of Major Advisor             Dr. L.N.Bhardwaj
3.       Title of Thesis                   Influence of VAM and crop residues on white
                                           root rot of apple
4.       Year of completion of Degree      1998
5.       Abstract of Thesis

        Among green amendments of ten different crops evaluated against Dematophora
necatrix causing white root rot of apple, white clover, black gram, wheat, maize, peas,
mungbean and soybean were found effective in reducing disease severity. In addition,
roots were efficiently colonized and chlamydospores were abundantly produced upon
inoculation by Glmus sp. and G. heterosporum (apple isolate). However, maximum VAM
colonization and spore population was observed in soybean and mungbean plants grown
in Glomus sp. inoculated soil. Similarly, root and shoot length were recorded maximum
in plants inoculated with Glomus sp. Treatments comprising of green amendments and
VAM fungi had less disease severity compared to green amendments and VAM fungi
alone. Maximum disease severity was observed in soybean and mungbean amended soil
inoculated with Glomus sp. This was followed by maize + Glomus sp., soybean + G.
heterosporum and mungbean + G. heterosporum. Inoculation of Glomus sp. in residue
amended soil (amended with soybean) efficiently colonized the apple roots and produced
maximum spore number per 100 g of soil. Maximum increase in growth parameters such
as height, stem diameter, leaf area, root length and dry weight was found in seedlings
grown in soybean, mungbean, pea and maize amended and Glomus sp. inoculated soil.,
Inoculation of soybean, mungbean and pea with VAM fungi, especially Glomus sp.
resulted in significant increase in mycorrhizal inoculation efficiently (MIE) of the plants.
1.       Name of the student and          Usha Devi (H-95-30-M)
         Admission No.
2.       Name of Major Advisor            Dr. Ved Ram
3.       Title of Thesis                  Studies on apricot rust and its management
4.       Year of completion of Degree     1998
5.       Abstract of Thesis

        The disease causes premature, moderate to heavy defoliation, besides this reduces
the biomass yield and overall health of the plant significantly. During the course of
present study the disease was found more severe in nursery plantations (51.50-64.86%) in
comparison to fruit bearing trees (23.23-63.46%). While studying the effect of weather
parameters on disease under orchard conditions, low temperature with high relative
humidity were found to favour development and spread of the disease. For the
germination of uredospores, 22oC was observed to optimum in laboratory conditions.
Studies on physiological specialization in Tranzschelia discolor showed that isolates of T.
discolor were highly specific, infecting only the original host from where the inoculum
was obtained. On the basis of symptoms, morphological characters and physiological
specialization the pathogen has been identified as T.discolor, f.sp. armeniacae. Out of 24
cultivars screened under natural epiphytotic conditions, three cultivars namely
Shakarpara, Fragmore Early and Kaisha were found highly resistant whereas rest of the
cultivars were found susceptible to varying degree. The foliar sprays of SAN-619, Contaf
plus Kavach and Contaf at 21 day intervals started prior to appearance of disease, were
found highly effective in disease management.
1.       Name of the student and         Savita Jandaik (H-96-24-M)
         Admission No.
2.       Name of Major Advisor           Dr. D.S.Guleria
3.       Title of Thesis                 Biology and management of Trichoderma during
                                         cultivation of Agaricus species
4.       Year of completion of Degree    1998
5.       Abstract of Thesis

        Two species of Trichoderma namely, T. viride and T. harzianum were isolated
from various components of mushroom compost. Between the two species, T. harzianum
was of more common occurrence as compared to T. viride irrespective of mushroom units
surveyed and seasons. The two Trichoderma species could establish on both types of
compost (pasteurized and unpasteurized). Maximum per cent inhibition of Agaricus
bisporus vegetative growth was recorded with T. harzianum. The per cent inhibition in A.
bisporus irrespective of Trichoderma species and temperature ranges. Per cent inhibition
in growth of A. bisporus was maximum in presence of T. harzianum at pH 7.0 followed
by T. viride at the same pH level. There was significant decrease in yield of A. bisporus
with corresponding increase in inoculum level of T. viride from 0.1 to 1.0 g/kg compost.
Similar trend in decrease of yield was also recorded with T. harzianum inoculum levels.
Carbendazim (Bavistin 50 WP) and thiophanate methyl (Topsin-M 50 WP) at 25 ppm
concentration each, did not exert any inhibitory effect on mycelial growth of either
Agaricus species. With two applications of either fungicide, yield was more with
thiophanate methyl in case of T. viride inoculation as compared to T. harzianum. Yield
of A. bisporus was significantly more in neem leaves amended wheat straw compost
irrespective of Trichoderma species and rate of amendment as compared to check (devoid
of plant material).
1.       Name of the student and        Anita Sharma (H-96-16-M)
         Admission No.
2.       Name of Major Advisor          Dr. L.N.Bhardwaj
3.       Title of Thesis                Studies on Phytophthora rot of strawberry
4.       Year of completion of Degree   1999
5.       Abstract of Thesis

        During survey, four types of rots viz., leather rot Phytophthora cactorum (Leb
and Cohn.) Schroet), ripe rot (P. nicotianae Breda de Haan), grey mould (Botrytis
cinerea Pers ex Fr.) and hard rot (Rhizoctonia solani Kuhn) were found associated with
fruits of strawberry of which P. cactorum was highly destructive. Young berries were
found more prune to infection than mature and ripened one. Oat meal and corn meal were
adjudged the best medium for maximum mycelial growth and sporulation. A temperature
of 25oC and pH 5.5 were optimum for vegetative growth and sporulation. Maximum
sporangial germination and zoospore liberation was recorded at 25 and 15oC and RH
between 88.5 – 92.9 and 96.1 – 100 per cent, respectively. Sprays of Ridomil MZ alone
(without mulch) and in combination with polythene and paddy straw mulch provided
excellent control of leather rot.
1.       Name of the student and         Manju Chaudhary (H-96-19-M)
         Admission No.
2.       Name of Major Advisor           Dr. S.K.Sharma
3.       Title of Thesis                 Variability in Dematophora necatrix causing
                                         white root of apple
4.       Year of completion of Degree    1999
5.       Abstract of Thesis

        Three isolates of Dematophora necatrix were found to be pathogenic to the apple
plants however, isolate D1 was most virulent and killed the plants within ten days of
inoculation. Physi8oogical studies showed that potato dextrose agar medium was best
solid medium for all three isolates, however, in liquid media, Sabouraud’s medium for D1
and D2 isolates and Coon’s medium for D3 isolate resulted in maximum mycelial dry
weight. All the isolates showed maximum growth at 20oCtemperaturee and 6.5 pH.
Sucrose in case of D2 and D3 isolates and lactose in case of D1 isolate proved to be the
best carbon source and amongst nitrogen sources, sodium nitrate (for D1 and D2 isolates)
and potassium nitrate (for D3 isolate) gave maximum fungal growth. Management studies
showed that 5 per cent gypsum and 2 per cent calcium carbonate gave compete control of
the disease. The disease was maximum at 100 per cent water-holding capacity of soil.
Under in vitro testing, Bavistin, Carben 50 and Phorate completely inhibited the mycelial
growth of all the isolates at all the concentrations tested. In pot experiments, maximum
control was obtained by Bavistin, Carben 50 and Phorate and in field studies, Bavistin
gave cent per cent disease control.
1.       Name of the student and          Rahul Katoch (H-97-28-M)
         Admission No.
2.       Name of Major Advisor            Dr. Sunita Chandel
3.       Title of Thesis                  Studies on Fusarium wilt of carnation
4.       Year of completion of Degree     1999
5.       Abstract of Thesis

        The survey revealed that the incidence was more in Mandi district (22.54%)
followed by Sirmour (19.10%), while the lowest incidence was recorded in district Kullu
(6.70%). The fungus produced typical characteristic symptoms of wilt within 20 days by
root dip inoculation where roots of cutting were dipped in inoculum of test fungus. Potato
dextrose agar and carnation leaf agar were rated best for maximum mycelial growth and
sporulation of the fungus. The fungus could grow between a temperature range of 15-
30oC with an optimum at 25oC. The fungal growth was obtained as highest at pH range of
5.5 to 6.5, through the fungus could multiply on a wide pH rage of 4-10. The best control
of carnation wilt was achieved at wider spacing of 30 x 30 cm followed by 25 x 25 cm.
Pine needles followed by mustard and neem cakes gave maximum control of the disease
when applied two months before planting of cuttings. Bavistin and Kri-Benomyl gave
complete inhibition of vegetative growth of the fungus under in vitro studies at
concentrations of 100 and 200 ppm, respectively. In field conditions, Bavistin gave
better results followed by Kri-Benomyl and both these fungicides were found highly
efficacious than other fungicides in controlling wilt disease besides increasing the flower
yield of the crop.
1.       Name of the student and         Gyatri Bhardwaj (H-96-17-M)
         Admission No.
2.       Name of Major Advisor           Dr. T.R.Shandilya
3.       Title of Thesis                 Studies on vermicompost as casing substrate for
                                         white button mushroom – Agaricus bisporus
                                         (Lange) Imbach.
4.       Year of completion of Degree    1999
5.       Abstract of Thesis

        Water holding capacity, pore space percentage, pH and electrical conductivity of
all the collected materials were evaluated and it was revealed that farm yard manure
(120%) had the maximum water holding capacity followed by 3 years old spent compost
(104%) and vermicompost normal (101%). Porosity also followed almost the same
pattern. Vermicompost – normal (N) had the highest salt concentration (780 µ mhos/cm).
Electrical conductivity of farm yard manure and spent compost was 438 and 410 µ
mhos/cm, respectively. Use of various combination ratios of vermicompost (N) + farm
yard manure resulted in maximum production of mushrooms when used in the ratio of
4:3 (v/v). There was gradual fall in pH levels from the date of casing to the end of
cropping in all the test combinations. In vermicompost (C) + farm yard manure, it came
down to 7.0, whereas in other two combinations (vermicompost (L) + farm yard manure
and farm yard manure + loam soil), it lowered down to 7.1. The electrical conductivity
increased with the progression of cropping in all the three test combinations. Among
various combinations, vermicompost (C) + farm yard manure (2:1; v/v) supported
maximum yield of Agaricus bisporus followed by vermicompost (L) + farm yard manure
when used in 1:1 ratio (v/v) and farm yard manure + loam soil (1:1; v/v). Vermicompost
(C) + farm yard manure (2:1; v/v) had the highest dry matter content of fruit bodies
followed by farm yard manure +loam soil (1:1; v/v) in the first flush. Yield of
mushrooms showed an increasing trend with the increase in moisture percentage of test
casing combinations at the time of casing. Application of spawned casing either grain
spawn @ 150 g and impregnated compost @ 450 g/bag casing material having 10 kg of
compost resulted in early pinning and higher yields of button mushroom.
1.       Name of the student and         Desh Raj (H-97-23-M)
         Admission No.
2.       Name of Major Advisor           Dr. S.K.Gupta
3.       Title of Thesis                 Studies on downy mildew of cucumber (Cucumis
                                         sativus L.) caused by Pseudoperonospora
                                         cubensis (Berk. and Curt.) Rostow.
4.       Year of completion of Degree    1999
5.       Abstract of Thesis


        Downy mildew (Pseudoperonospora cubensis (Berk. and Curt.) Rostow.) of
cucumber appeared in moderate to severe form in major cucumber growing areas of
Himachal Pradesh during 1998 crop season. Maximum sporangial germination was
recorded at 20oC but their relative rate of germination was maximum between 1 and 2
hour of incubation. Maximum distribution of sporangia was recorded at a height of 25 cm
above the ground level. The mean air temperature, relative humidity and rainfall
considerably influenced the downy mildew development. The multiple regression
equation revealed that a unit increase in temperature could reduce disease severity by
5.4672 units, whereas a unit increase in RH and rainfall could increase the disease
severity by 0.2711 and 0.1894 units, respectively. Cultivar Chitradurga was found
resistant against the disease which can be utilized in breeding programme for developing
resistant varieties. Among fungitoxicants tested Ridomil MZ (1000 ppm) caised
maximum reduction in sporangial formation followed by Acrobat MZ (1000 ppm). In
protective spray programme, maximum disease control as well as fruit yield and
minimum infection rate ® and AUDPC were provided by spray application of Ridomil
MZ (0.25%) and Acrobat MZ (0.25%). Ridomil MZ (0.25%) also exhibited maximum
anti-sporulant activity i.e. upto 7 days.
1.       Name of the student and          Ramesh Kashyap ( H-96-20-M)
         Admission No.
2.       Name of Major Advisor            Dr. A. K. Gupta
3.       Title of Thesis                  Effect of apple leaf litter microflora
                                          pseudothecial     development of Venturia
                                          inaequalis (Cke.) Wint.
4.       Year of completion of Degree     1999
5.       Abstract of Thesis


        The investigations were conducted to know the pattern of decomposition of fallen
scabbed apple leaves in unsprayed apple orchard at different altitude locations in district
Kullu, Himachal Pradesh, India. Maximum decomposition was observed in samples
collected on 30th September at Bajaura. Maximum number of isolates from apple leaf
litter belonged to fungi (42) followed by bacteria (10) and actinomycetes (7). In vitro
screening of different isolates reveled that maximum colonization (> 70 %) of various
stages of apple leaf discs was done by Penicillium brevicompactum, Fusarium
sporotrichiodes, Trichoderma hamatum, Trichothecium roeseum and Aspergillus
funiculosus. Under orchard conditions, T. hamatum applied at 30x 106 CFU-ml showed
maximum reduction in pseudothecial density (86.62 %), number of asci per
pseudothecium (86.39 %), ascospore productivity (85.29 %) and pseudothecial maturity
(85.52 %).
1.       Name of the student and          Sachin Upmanyu (H-96-23-M)
         Admission No.
2.       Name of Major Advisor            Dr. R.C.Sharma
3.       Title of Thesis                  Studies on purple blotch of onion caused by
                                          Alternaria pomi (Ellis) Cif.
4.       Year of completion of Degree     1999
5.       Abstract of Thesis


       Investigations on purple blotch of onion were undertaken to study the occurrence
of the disease, physiology of the pathogen, identification of sources of resistance and
management of disease by using chemicals. Maximum disease incidence and severity of
purple blotch of onion was recorded at Pandah. The disease had a significant effect on the
seed yield and quality. Umbels from seed stalks with 100 per cent disease severity
showed shrivelled seeds yielding minimum seed weight of 2.00 grams only (Av. of 3
umbels). Among various media tested, fungus preferred potato dextrose medium
followed by Richard’s medium which was used as basal medium for the growth of
Alternaria porri for subsequent physiological studies. The fungus grew best at a pH of
4.5 and it preferred 25oC temperature for maximum growth. Fungus also preferred
maltose and potassium nitrate as best sources of carbon and nitrogen, respectively for its
growth. None of the cultivars was free from the disease, however, three cultivars viz.,
408, 581 and Nasik Red had minimum disease index. Captafol among non-systemics and
penconazole and hexaconazole among systemics were found most effective in inhibiting
the mycelial growth of the fungus. In field trial, Ridomil MZ proved most effective
followed by hexaconazole, penconazole, difenoconazole and mancozeb whereas among
neem oils none was found effective under in vitro as well as in vivo studies.
1.     Name of the student and         Minakshi Sharma (H-97-24-M)
       Admission No.
2.     Name of Major Advisor           Dr. K.R.Shyam
3.     Title of Thesis                 Studies on late blight of tomato (Lycopersicon
                                       esculentum Mill.) caused by Phytophthora
                                       infestans (Mont.) deBary
4.     Year of completion of Degree    1999
5.     Abstract of Thesis

             Studies were conducted on different aspects of late blight of tomato
     caused by Phytophthora infestans (Mont.) deBary. The disease incidence and
     severity ranged between 20.40 to 57.80 and 7.58 and 56.66 per cent, respectively
     in Solan district of Himachal Pradesh during 1999. Typical symptoms of the
     disease were observed on leaves, stems, branches and fruits of tomato. Based on
     morphological characteristics, the pathogen associated with the disease was
     identified as Phytophthora infestans (Mont.) deBary. Pathogen was found
     pathogenic only to various hosts belonging to family solanaceae. Among the six
     solid media tested, maximum mycelial growth and sporangial production was
     observed on rye agar and minimum on gram sucrose agar. Fungus grew best at
     15oC and 100 per cent relative humidity. Sporangial germination was maximum
     in dew water (91.12%) and minimum in potassium nitrate solution (45.28%). All
     highest inoculum concentration used incubation period was minimum (52 h) and
     disease severity was maximum (94.44%). With the increase in leaf wetness period
     from 2 to 24 h, a progressive decline in incubation period from 74 to 48 h and 98
     to 72 h was recorded for leaves and fruits, respectively. Incubation periods were
     shortest at 100 per cent RH and temperatures of 10 and 15oC in leaves and fruits,
     respectively. Screening of different cvs./germplasm lines showed that all lines
     were susceptible except Sel-101 which was moderately resistant to the disease.
     Dithane M-45, Blitox-50, Ridomil MZ, captafol, Acrobat MZ, Acrobat and
     Akomine were found to inhibit the mycelial growth of the fungus upto 100 per
     cent level under in vitro conditions. Under field conditions, Ridomil MZ was most
     efficacious in reducing disease incidence and severity.
1.       Name of the student and            Reshu Garg (H-96-21-M)
         Admission No.
2.       Name of Major Advisor              Dr. P.D.Thakur
3.       Title of Thesis                    Investigations on a phytoplasma disease of peach
                                            (Prunus persica L. Batsch)
4.       Year of completion of Degree       1999
5.       Abstract of Thesis

         A phytoplasma disease of peach was studied in the present investigations with
respect to its symptomatology, transmission, host range, detection (electron and
fluorescent microscopy) and remission of symptoms by the use of antibiotic
(oxytetracycline hydrochloride). Surveys of peach orchards at different locations of
district Sirmour were conducted to record the incidence. Available germplasm of peach
was also screened to find out the source of resistance against the phytoplasma infection.
Prevalence of disease was noted in 46 orchards out of 64 orchards surveyed with an
incidence ranging from 0.5 to 70 per cent. Initial symptoms of the disease were exhibited
on 6 weeks old foliation in the form of chlorosis and upward rolling. Subsequently, the
symptoms on the trees were followed by yellowing, red spotting, tattering, enlarged
prominent veins and early leaf fall. Fruits were smaller and shrivelled which often
dropped prematurely. The pathogen was found to significantly affect the blooming
intensity and fruit set in diseased plants. It was transmissible through grafting and
budding but not through dodder (Cuscuta reflexa). Experimentally, the pathogen was
found to infect the following stone fruit species namely almond, bitter almond, nectarine
and wild peach. The association of phytoplasma with the disease was confirmed through
detection under electron microscope which revealed the presence of pleomorphic bodies
in sieve tube elements of phloem. Fluorescent microscopic detection of the pathogen in
the phloem of a diseased sample by conducting DAPI (4’-6 diamidiono-2 phenylindole
2HCl) test also confirmed the phytoplasmal etiology of the disease. In DAC indirect
ELISA test, no serological reaction of the present isolate was found with the crude
antiserum of eastern X pathogen obtained from Canada. The antibiotic (OTC-HCl)
treatment was found to remit the symptoms of ailing trees indicating the association of
phytoplasma with the diseases. All doses tried (1g, 2g and 3g per tree) in the two methods
(pressure injection and pipette method) proved effective with significant reduction in
disease index in comparison to untreated trees. Out of the 46 cultivars evaluated to find
out the sources of resistance against the isolate studied, only one cultivar namely Early
Red Free has been found to be resistant to infection under both natural as well as
experimental conditions. The typical symptoms produced by the disease, it has been
tentatively identified as peach X (yellow leaf roll strain) similar to that prevalent in north
America.
1.       Name of the student and          Anil Kumar (H-97-21-M)
         Admission No.
2.       Name of Major Advisor            Dr. P.D.Thakur
3.       Title of Thesis                  Biological and serological detection of apple
                                          chlorotic leaf spot virus in apple
4.       Year of completion of Degree     2000
5.       Abstract of Thesis

        In biological detection of apple chlorotic leaf spot trichovirus (ACLSV) in apple,
R 12740-7A was found suitable woody indicator. DAS and DAC-ELISA at maximum
dilutions of 10-2, 10-2 and 10-3 of antigen, antibody and enzyme conjugate, respectively
were found suitable for reliable detection of ACLSV. The virus was detected in leaves,
petal, bark, root and fruit of infected tree during different months of the year through
ELISA. The concentration of the virus was maximum in bark in the month of August. A
mixed infection of ACLSV and ApMV was also found in some infected plants of apple.
Trees of sixteen cultivars of apple were selected as virus tested trees after serological
indexing against ACLSV, ASGV, ApMV and ToRSV.
1.       Name of the student and          Renu Bala (H-97-29-M)
         Admission No.
2.       Name of Major Advisor            Dr. L.N.Bhardwaj
3.       Title of Thesis                  Studies on Marssonina blotch of apple
4.       Year of completion of Degree     2000
5.       Abstract of Thesis

         Detail studies on symptomatology, morphology and pathogenicity were
conducted. Based on this, the causal agent was identified as Marssonina coronaria (Ell.
et. J.J. Davis) J.J. Davis. The nutrient requirements for test fungus was studied in vitro
by slide germination technique. Rose leaf extract, sucrose, asparagine, ascorbic acid,
ferrous sulphate were found the best nutrient solution for conidial germination and
formation of germtube length. The test fungus could survive on the following infected
leaves for more than a year under orchard, refrigerated and laboratory conditions. Two
apple cultivars, Granny Smith and Tydeman’s Early Worcester were found resistant to
the pathogen. Carbendazim (0.025%) combined with mancozeb (0.25%), sprayed thrice
at15 days interval during June to August almost provided complete control of this
disease.
1.       Name of the student and          Brijesh Kumar Kamal (H-97-22-M)
         Admission No.
2.       Name of Major Advisor            Dr. Ved Ram
3.       Title of Thesis                  Studies on grey mould rot of strawberry and its
                                          management
4.       Year of completion of Degree     2000
5.       Abstract of Thesis

         As high as 90 per cent yield losses have been reported during wet growing season.
During the course of present study, the disease incidence varied from 4.5-30.5 per cent,
however, maximum (30.5%) was recorded in Dhaulakuan area of Sirmaur district of
Himachal Pradesh. Symptoms on fruit appeared as light brown areas, which were soft at
first, turned dark brown followed by the appearance of greyish mycelium which turned
powdery at the later stage of disease development. Under high humidity conditions, green
berries, sepals and fruit stalks were also found covered with grey mycelium. The shortest
incubation period of the pathogen was observed on fully ripened berries (31 h) followed
by mature and immature berries, respectively. Botrytis cinerea produced maximum
vegetative growth on potato dextrose agar and glucose asparagine medium while
maximum sporulation occurred in cornmeal and oatmeal agar, respectively. Sodium
nitrate was observed as the best nitrogen source for the growth of B. cinerea. A
temperature of 25oC, RH of 100 per cent and pH of 6 supported maximum growth of B.
cinerea. Weather parameters were found to put considerable effect on disease
development under field conditions. The disease incidence was found positively
correlated with relative humidity and rainfall and negatively with temperature. All the
strawberry cvs. evaluated for their resistance against B. cinerea showed highly
susceptible reaction. Bavistin (200 ppm), Captan (2000 ppm), Contaf (200 ppm),
Rubigan (250 ppm) and Dithane M-45 (3000 ppm) completely inhibited the vegetative
growth of B. cinerea under in vitro conditions. Bavistin (0.05%) or Captan (0.30%) along
with polythene mulch resulted in maximum disease control and enhanced the fruit yield
under field conditions.
1.       Name of the student and          Sonali (H-98-26-M)
         Admission No.
2.       Name of Major Advisor            Dr. A. K. Gupta
3.       Title of Thesis                  Management of seedling blight (Sclerotium rolfsii
                                          of apple through non-chemical methods
4.       Year of completion of Degree     2000
5.       Abstract of Thesis

        Soil microflora (16 fungal, 6 bacterial and 3 actinomycetes), plant materials and a
neem oil formulation were evaluated against Sclerotium rolfsii Sacc. causing seedling
blight in apple nurseries. Maximum reduction (77.41 %) in radial growth was observed in
Bacillus sp. strain 1 followed by Trichoderma viride (72.22 %). Different plant materials
and neem oil formulation were also evaluated. Hundred per cent inhibition was observed
in mustard cake + neem oil, neem cake + deodar needle + neem oil and mustard cake +
neem cake + pine needles + neem oil. Trichoderma viride alone and in combination with
neem oil + mustard cake and neem oil + neem cake + deodar needles provided cent per
cent control of seedling blight under pots when applied along with pathogen or 15 days
before, at the time of applying pathogen and 15 days after applying pathogen in the pots.
T. viride was also effective under field resulting only 2.78 per cent disease incidence. It
also enhanced the growth of apple seedlings in nursery.
1.       Name of the student and        Ritu Duggal (H-98-25-M)
         Admission No.
2.       Name of Major Advisor          Dr. Ved Ram
3.       Title of Thesis                Studies on Marssonina leaf blotch of apple
4.       Year of completion of Degree   2001
5.       Abstract of Thesis

        Maximum disease severity was recorded in Solan district (60.65%) followed by
Shimla, Sirmaur and Kullu districts and minimum was in Mandi district. Pathogenicity
test conducted on young potted apple plants showed that typical disease symptoms were
produced after 10-12 days of inoculation and complete defoliation occurred 12-15 days
after the appearance of first visible symptoms. The disease incidence and severity were
found to be positively correlated with temperature, relative humidity and rainfall. The
pathogen survived in the infected apple leaves, both sprayed with and without urea, for
one year in the form of fruiting bodies (acervuli) under laboratory refrigerated and
orchard conditions. the per cent spore germination was more in unsprayed leaves than in
sprayed ones. Bavistin (500 ppm), SAAF (2500 ppm), Dithane M-45 (3000 ppm) and
Noor (750 ppm) were found to be the best fungicides in inhibiting conidial germination
of Marssonina coronaria. Minimum germ tube length was recorded in Dithane M-45
(3000 ppm) and Tohfa (750 ppm). Out of the botanicals, olive oil (75 ppm), followed by
clove oil (75 ppm) were found to be nest for inhibiting conidial germination of M.
coronaria. Under field conditions, Tohfa (0.075%), followed by Noor (0.075%) provided
excellent control of Marssonina leaf blotch of apple and per cent leaf fall was also
minimum with these fungicides.
1.       Name of the student and          Ashu Sharma (H-98-20-M)
         Admission No.
2.       Name of Major Advisor            Dr. S.K.Gupta
3.       Title of Thesis                  Studies on Crown Rot of French bean caused by
                                          Sclerotium rolfsii (Sacc.)
4.       Year of completion of Degree     2001
5.       Abstract of Thesis

        Crown rot of French bean caused by Sclerotium rolfsii (Sacc.) was found to be
more severe in Solan district than Kullu. The disease incidence ranged from 10.66 to
56.33 per cent during 1999 crop season. Characteristic symptoms appeared as a dark
brown, water soaked lesions on the stem at collar region just below the soil line followed
by yellowing of leaves and production of a white mouldy growth interspersed with
sclerotia at the base of stem, under surface of leaves and pods. Mycelium of the fungus
was white, coarse and fan shaped. Hyphae are hyaline, branched and septate and
characterized by the presence of clamp connections. Sclerotia are brown, smooth, round
or irregular and 1-3 mm in diameter. V-8 juice agar, oatmeal agar and PDA; 25-30oC and
5-6 were found to be the best media, temperature and pH range, respectively, for mycelial
growth and sclerotial production of the pathogen. S. rolfsii was found to be pathogenic to
various plants belonging to families Solanaceae, Cucurbitaceae, Cruciferae,
Leguminosae, Chenopodiaceae and Compositae with varied degree of aggressiveness.
Soil temperature ranging between 25 to 30oC and 50 per cent soil moisture level were
found to be most conducive for disease development. Out of the 42 cultivars screened
against S. rolfsii, none was found to be resistant. All the cvs./ lines were moderately
resistant to highly susceptible. Under in vitro conditions, Topas, Contaf, Antracol and
Indofil M-45 were found to be most effective in inhibiting mycelial growth. Sclerotial
germination was found to be minimum with Topas followed by Antracol and Indofil M-
45. Spray applications of Antracol were found to be most effective in reducing disease
incidence and increasing pod yield, followed by Captaf and Indofil M-45. Among the
biocontrol agents, Gliocladium virens and Trichoderma viride were found to be most
effective against S. rolfsii.
1.       Name of the student and           Chirag Singh (H-98-22-M)
         Admission No.
2.       Name of Major Advisor             Dr. V.P.Sharma
3.       Title of Thesis                   Biology and management of Mycogone
                                           perniciosa Magn. causing web bubble of white
                                           button mushroom
4.       Year of completion of Degree      2001
5.       Abstract of Thesis

         Incidence of the disease, irrespective of locations and year of survey, ranged from
0 to 80 per cent in different mushroom growing units. Pasteurized sporocarps/pin heads
of Agaricus bisporus develop monstrous shapes which often do not resemble mushrooms.
Maximum reduction in yield (48.23%) occurred when 1.0 per cent inoculum was added
at casing stage. In addition to A. bisporus, A. bitorquis and Pleurotus eryngii were also
found susceptible to M. perniciosa. Water splash, physical contact and insect-pests
(Sciarid, phorid, springtail) along with mites were found to spread/disseminate M.
perniciosa. Thermal death point of the pathogen was found to be in between 40 to 50 oC
as all, mycelium, conidia, and chlamydospores failed to exhibit growth/germination when
exposed to 50oC and above for 30 minutes. Drenching of mycelial discs of M. perniciosa
and A. bisporus with formalin (1.0, 1.5, 2.0%) resulted in cent per cent inhibition in the
mycelial growth of both the fungus. Two sprays (first at casing and second 10 days after
casing) of Sporgon (0.1%) and Dithane M-45 (0.15%) gave 97.33 and 94.66 per cent
control of wet bubble, respectively.
1.       Name of the student and          Sanjeev Kumar (H-97-30-M)
         Admission No.
2.       Name of Major Advisor            Dr. S.C.Chowfla
3.       Title of Thesis                  Studies on mosaic disease of pea (Pisum sativum
                                          L.)
4.       Year of completion of Degree     2001
5.       Abstract of Thesis

        The investigations were undertaken to identify the different virus(es) responsible
for causing mosaic disease of pea (Pisum sativum L.) in Solan district of Himachal
Pradesh. Surveys conducted to record the incidence of pea virus disease during the year
1999 revealed that the incidence ranged between 14 to 34 per cent in different localities
of Solan. The identification of the isolates was based on symptomatology, transmission,
biophysical properties, host range, particle morphology and serological relationships by
employing direct antigen coating (DAC) indirect form of ELISA. On the basis of these
characters, all the three isolates i.e. P-I, P-II and P-III to see their comparative
resistance/susceptibility reaction against the most prevalent pea virus isolate (P-I).
However, none of the varieties/cultivars/collections were found to be resistant.
1.       Name of the student and          Promil Kapoor (H-99-17-M)
         Admission No.
2.       Name of Major Advisor            Dr. Anil Handa
3.       Title of Thesis                  Investigations on       a    viral   disease       of
                                          chrysanthemum
4.       Year of completion of Degree     2001
5.       Abstract of Thesis

        The surveys conducted during the year 1999-2000 revealed the incidence of virus
diseases between 0 to 39 per cent in different localities of Solan district. The symptoms
evoked by the virus isolate (C-1 and C-II) were chlorotic and/or necrotic spots on leaves,
prominent green vein banding and occasional flower deformation. Both the isolates were
transmissible through sap and isolate C-II alone was transmissible through an aphid
vector (Myzus persicae). The isolates infected members of the families amaranthaceae,
chenopodiaceae, compositae, cucurbitaceae, leguminosae, polemoniaceae and
solanaceae. Both the isolates differed in their biophysical properties. Electron
microscopic studies of the virus isolate C-I revealed the presence of isometric virus
particles measuring 80 nm in size whereas isolate C-II had flexuous particles with a
modal dimension of 685x13 nm. Results obtained in direct DAS-ELISA revealed that
isolate C-I was tomato spotted wilt tospovirus and C-II was chrysanthemum B carlavirus.
Indirect DAC-ELISA tests revealed that isolate C-I was serologically related to
impatiens necrotic spot tospovirus (INSV) and isolate C-II serologically related to
carnation latent carlavirus (CLV). It was concluded that the virus isolate C-I is tomato
spotted wilt tospovirus, a member of the genus tospovirus and isolate C-II is
chrysanthemum carlavirus, a member of the genus carlavirus.
1.       Name of the student and         Shyama Nand (H-99-19-M)
         Admission No.
2.       Name of Major Advisor           Dr. Sunita Chandel
3.       Title of Thesis                 Studies on biological control of Fusarium
                                         yellows of gladiolus
4.       Year of completion of Degree    2002
5.       Abstract of Thesis

        The studies were carried out on biological control of Fusarium yellows caused by
Fusarium oxysporum f.sp. gladioli (Snyd. and Hans.). Nine species of fungi and two
isolates of bacteria were isolated from the rhizosphere of gladiolus which were found
more or less antagonistic to Fusarium yellows pathogen. Besides these, Trichoderma
hamatum and T. longibrachiatum were also in vitro tested against the pathogen. Amongst
these, Trichoderma harzianum, T. viride and T. virens were found highly effective
biocontrol agents (BCAs) controlling Fusarium yellows. Eleven different organic
substrates were tested for mass production of above three BCAs of which wheat bran
followed by cotton cake gave good results. A temperature of 25oC was found most
suitable for their mass production. In disease management experiments both in the
storage as well as field, slurry method of application of T. harzianum and T. viride was
most effective in managing the Fusarium yellows. Placement method of application of
above biocontrol agents at 15 days before or at sowing time gave maximum disease
control with encourage effect on plant growth in vivo. Neem cake in association with T.
harzianum and T. viride gave highest disease control as compared to cotton cake and
mustard cake. Of the 11 different fungicides tested under in vitro, Bavistin, SAAF,
Triadimefon, Captan, Dithane M-45, Kavach and Thiram showed compatible reactions
with above two biocontrol agents. While in integrated experiment biocontrol agent i.e. T.
harzianum along with neem cake and Bavistin gave maximum disease reduction and
improved the overall growth of gladiolus.
1.       Name of the student and        Rajeev Tegta (H-99-18-M)
         Admission No.
2.       Name of Major Advisor          Dr. A. K. Gupta
3.       Title of Thesis                Effect of leaf litter fungi in biological suppression
                                        of Venturia inaequalis (Cke.) Wint. causing apple
                                        scab.
4.       Year of completion of Degree   2002
5.       Abstract of Thesis

        Maximum decomposition of fallen apple leaves over orchard floor in an
unsprayed orchard at Bakhnewal in district Shimla, Himachal Pradesh on 29th February,
2000. Maximum fungi (78.67 fungal colonies/g leaf litter) were also isolated at
Bakhnewal. Chaetomium globosum, Cladosporium herbarum, Trichoderma hamatum, T.
harzianum and T. viride showed more than 70 per cent colonization of non-sterilized
scabbed green and senescent apple leaf discs under in vitro conditions. Chaetomium
globosum at 30 x 106 CFU-ml was also most effective in reducing ascospore productivity
(64.87 %) and pseudothecial maturity (64.58 %) after five months of over-wintering of
treated leaves over orchard floor.
1.       Name of the student and        Umang Bhardwaj (H-99-21-M)
         Admission No.
2.       Name of Major Advisor          Dr. H.R.Gautam
3.       Title of Thesis                Studies on root rot of strawberry
4.       Year of completion of Degree   2002
5.       Abstract of Thesis

       The incidence of root rot of strawberry during the year 2000 and 2001 was
recorded highest (43 and 44.7%) at Jachh followed by Dhaulakuan, Nauni and least at
Shimla. Among the different cultivar, Chandler had the highest incidence of disease
during the year 2000 and 1001. The symptoms of the disease start as wilting, yellowing
of leaves along the margin before plant completely turn brown in colour, wilt and then
rot. Mycelium of the fungus was white, coarse and fan shape. Hyphae were hyaline,
branched, septate and characterized by clamp connections. Sclerotia were brown, smooth,
round to irregular, 103 mm in diameter. PDA was found to be most suitable media for
growth followed by Richards agar and Czapeks Dox agar while 25oC temperature was
found optimum for the growth of the fungus. Soil solarization with transparent
polyethylene sheet (25 µm) increased the soil temperature by 10.2 and 6.7oC at 7 and 15
cm soil depth during 2000 and by 10.6 and 8.5oC at 7 and 15 cm soil depth during 2001.
Increase in soil temperature completely inhibited sclerotial germination at 7 cm soil
depth after 40 days of soil solarization. Among 11 fungicides evaluated under in vitro
conditions SAAF was found to give 100 per cent reduction in mycelial growth results
followed by Companion and Stop. Among three different sets of treatment consisting of
drenching, root dip + drenching and root dip + solarization, solarization + root dip in
SAAF was found to give best control of the disease which also resulted in increase in
shoot length, root length, number of flowers, number of fruits, number of runners,
average fruit weight and fruit yield. The drenching + root dip in SAAF was found the
next best treatment followed by drenching in SAAF.
1.       Name of the student and          Sameer Singh Rana (H-2000-63-M)
         Admission No.
2.       Name of Major Advisor            Dr. P.D.Thakur
3.       Title of Thesis                  Investigation on a viral disease of carnation
4.       Year of completion of Degree     2002
5.       Abstract of Thesis

        A virus disease affecting carnation was found to exhibit characteristics symptoms
of mottling, leaf streaking, reduction in leaf size and colour breaking in some cultivars.
Preliminary serological studies revealed mixed infection of atleast two virus viz.,
carnation latent carlavirus and carnation mottle carmovirus in carnation. Detail
investigations were conducted on CarMV only. For mechanical transmission of the virus,
acetate buffer (0.2M), citrate buffer (0.1M), phosphate buffer (0.1M and Mcllvaine’s
buffer were found to give maximum infectivity of the virus in terms of local lesions
produced per centimeter square of leaf areas. However, acetate buffer (0.2M) at pH
ranging from 4.6 to 4.8 was found to be best for mechanical transmission of the virus.
The virus was found to infect a few host plants belonging to families amaranthaceae,
chenopodiace, cucurbitaceae and solanaceae. The virus had TIP of 85.90oC, DEP of
1:1,00,000 to 1:10,00,000 and LIV was 77 days at room temperature and 84 days at
refrigerated conditions. In serological studies, maximum detection of 10-3, 2x10-2 and 10-7
of antigen, antibody and enzyme conjugate in DAC-ELISA and dilution of 10-2 for
antigen and dilution of 2x10-2 for antibody and enzyme conjugate in DAS-ELISA
resulted in reliable detection of the virus. Electron microscopic examination revealed the
virus to be isometric bearing dimension ranging from 30-32 nm in diameter. On the basis
of different identification parameter virus was identified as a member of Tombus viridae
genus Carmovirus as carnation mottle Carmovirus. All the forty varieties screened
revealed high incidence of viral disease.
1.       Name of the student and         Kailash Kaushal (H-2000-60-M)
         Admission No.
2.       Name of Major Advisor           Dr. R.C.Sharma
3.       Title of Thesis                 Studies on the epidemiology and management of
                                         purple blotch of onion
4.       Year of completion of Degree    2003
5.       Abstract of Thesis

        Purple blotch disease incidence and index in onion seed crop at Nauni was
88.51per cent and 61.27 per cent, respectively. The disease affected the plant height,
number of scapes per bulb, number of umblets per umbel and seed weight adversely.
Spore germination was maximum at 25oC. Concentration of carbon sources was found
inversely proportional to spore germination. Temperature and rainfall were positively
correlated with disease incidence. Al the 12 genotypes screened against this disease were
susceptible. Ridomil –MZ was found best in inhibiting the mycelial growth of the fungus
followed by SAAF and mancozeb. Under field conditions, Ridomil –MZ was best in
checking the disease followed by SAAF, mancozeb and hexaconazole.
1.       Name of the student and            Rajesh Kumar (H-2000-62-M)
         Admission No.
2.       Name of Major Advisor              Dr. Satish K.Sharma
3.       Title of Thesis                    Studies on bacterial wilt of tomato caused by
                                            Ralstonia solanacearum (Smith) Yabuuchi et al.
4.       Year of completion of Degree       2003
5.       Abstract of Thesis

         The incidence of the disease ranged from 10 to 100 per cent. Maximum disease
incidence 9100%) was at Kalhog-Shadhupul in district Solan. However, no disease was
observed in Shimla district. Shorter incubation period (12 days) was observed in bacterial
suspension drenching method then root dip method (14 days). With the increase in soil
moisture and soil temperature from 8.00 to 17.53 per cent and 20.9 to 31.1oC,
respectively, there was a progressive increase in disease incidence, being maximum at
17.53 per cent soil moisture and 31.1oC soil temperature. Co-efficient of multiple
determination (R2) showed that 93.61 per cent change in disease development was due to
soil hydrothermal regimes. Amendment of soil with oil cakes increased the population of
bacteria, actinomycetes and Ralstonia solanacearum except for neem cake which reduced
the population of R. solanacearum and fungi. All the amendments reduced the incidence
of bacterial wilt and saw dust gave maximum disease control (70.37%) and delayed
symptoms appearance by about a fortnight. Management of bacterial wilt by hot water
seed treatment (50oC for 30 min.) and application of bleaching powder (15 kg ha -1) was
found most efficacious, thus resulting in maximum disease control (62.08%) and increase
in fruit yield (50%). The exposure of twenty-six genotypes of tomato to bacterial wilt in
sick soil in field at two different localities and in pots resulted in tailoring two genotypes
viz., AI-14 and 1794, completely free from disease.
1.       Name of the student and          Neel Gagan Verma (H-2000-61-M)
         Admission No.
2.       Name of Major Advisor            Dr. Ved Ram
3.       Title of Thesis                  Studies on almond rust caused by Tranzschelia
                                          discolor f.sp. dulcis
4.       Year of completion of Degree     2003
5.       Abstract of Thesis

         Rust caused by Tranzschelia discolor (Fekl.) Tranz. & Liv. f.sp. dulcis Bolkan et
al., is one of the destructive fungal disease of almond, wherever grown in the world. The
disease causes premature, moderate to heavy defoliation, besides this reduces the biomass
yield and overall health of the plant significantly. During the course of present study
prevalence of almond rust was not recorded from most of the localities surveyed in Solan
and Sirmour districts. In those localities where the disease appeared during 2001 and
2002, pathogen attacked nursery plants more severely (53.25 – 68.56%) in comparison to
fruit bearing trees (1.64-6.35%). Intensity of the disease was found more under dry
temperate conditions of Himachal Pradesh (54.53-66.35%) as compared to its severity in
mid-hill areas of the state (1.64-38.61%). While studying the effect of weather
parameters on disease under dry temperate conditions (RHRS, Sharbo) rainfall was
found essential for the initiation of disease, while temperature (19.23.5oC) and relative
humidity (50-70%) played significant role in further development and spread of the
disease. For the germination of uredospores, 22oC was observed optimum in laboratory
conditions. Pathogenicity test was carried out in vitro and rust symptoms appeared after
eight days of uredospores inoculation on almond leaf of susceptible cultivar Non Pareil.
Under dry temperate conditions of Himachal Pradesh, pattern of rust development on
different almond cultivars was variable. However, most of the cultivars were severely
infected during the month of September. Almond cultivars screened under natural
epiphytoti conditions were found either susceptible or highly susceptible to rust pathogen
except California Paper shell which exhibited moderately susceptible reaction against T.
discolor f.sp. dulcis. Best control of the disease was achieved with Folicur, Tilt and
Contaf when sprayed five times during the season at 3- week intervals in both preventive
as well as post-symptoms applications.
1.       Name of the student and           Biri Singh Attar (H-2001-37-M)
         Admission No.
2.       Name of Major Advisor             Dr. N.P.Dohroo
3.       Title of Thesis                   Studies on leaf blight of Colocasia caused by
                                           Phytophthora colocasiae Racib.
4.       Year of completion of Degree      2003
5.       Abstract of Thesis

         Leaf blight of Colocasia was studied in the present investigation with regard to its
incidence, etiology, epidemiology, cultural requirement of the fungus and management of
the disease. The disease was found to be prevalent in all the colocasia growth areas of
Himachal Pradesh with a disease incidence ranging from 3.33 to 88.24 per cent during
2002. Phytophthora cococasiae Racib. was identified as the causal organism of the
disease. The characteristic symptoms evoked by the disease were studied. Morphological
characters of the fungus viz., hyphae, sporangia, sporangiophores, papillae, oospores and
chlamydospores were investigated. Rye meal agar and Richard medium supported
maximum growth of the fungus at 25oC and pH 5.5. Brinjal, beans, capsicum, tomato,
chilli, colocasia and okra were found to be in the host range of fungus. 67.11 per cent of
the disease was found to be a result of air temperature, humidity and rainfall. Fusarium
spp. were found dominating on the surface of corms and cormels in storage. Unilax,
Antracol, Dithane M-45, Ridomil MZ were found to be effective against the pathogen in
vitro and under field conditions. In storage, minimum incidence of corm rot was found in
Ridomil MZ, Captaf, Dithane M-45 and Trichoderma harzianum. Trichoderma viride, T.
virens and T. hamatum were found biostatic against the pathogen in vitro. Three cultivars
i.e. SC2 (Solan), SC3 (Sirmaur) and SC7 (Shimla) showed moderately resistant reaction
against the disease while Muktakeshi was found to exhibit highly susceptible reaction in
the present study.
1.       Name of the student and          Vanita Chandel (H-2000-64-M)
         Admission No.
2.       Name of Major Advisor            Dr. (Mrs.) Sunita Chandel
3.       Title of Thesis                  Studies on Septoria leaf spot of chrysanthemum
4.       Year of completion of Degree     2003
5.       Abstract of Thesis

        Septoria leaf spot disease was studied in the present investigations with regard to
its severity, physiological studies and management practices. The disease was round to be
prevalent in all the chrysanthemum growth areas under survey with maximum of 45 per
cent disease severity at Nauni of Solan district. Sepotria obesa Syd. Was identified to be
associated with the disease. The characteristics symptoms evoked by the disease were
oval brown spots of 1.5 cm in diameter often on leaf margins, which later shriveled and
remained hanged on to the stem. Amongst different solid and liquid media tested, potato
dextrose agar, chrysanthemum leaf extract agar and Subouraud’s medium supported
maximum growth and sporulation of the fungus. Fungus could grow at a temperature
range of 5-30oC with an optimum at 25oC. Vegetative growth and sporulation was
maximum at pH 6.0 and 7.0. The fungus multiplied to maximum with regard to
vegetative growth and sporulation when supplemented with dextrose as carbon and urea
as nitrogen sources. Out of different ratios of carbon and nitrogen, 60:2 ratio was found
best in supporting vegetative growth and sporulation of the fungus. Conidia of Septoria
obesa germinated maximum in glucose and urea when used a substrates. Whereas
thiamine hydrochloride and glycine used as vitamin and amino acid supported maximum
conidial germination. Under epidemiological studies, disease severity was found
maximum at 25oC and 98.5 per cent relative humidity. Among various meteorological
factors studied rainfall and relative humidity were found positively correlated with the
disease severity. In the management studies, polythene sheet practiced as mulch was
found best in reducing the disease severity. Lower leaves removed upto 10inches height
also decreased the disease severity. Only two cultivars out of 107 cultivars were found
resistant to the disease under germplasm evaluation studies. Of the various fungicides
screened under in vitro and in vivo conditions against S. obesa, Contaf, Roverol, SAAF
and Dithane M-45 inhibited the maximum fungal growth and reduced the disease severity
by giving maximum disease control.
1.       Name of the student and           Ashutosh Bhaik (H-2001-36-M)
         Admission No.
2.       Name of Major Advisor             Dr. Anil Handa
3.       Title of Thesis                   Investigations on a viral disease of Lilium
4.       Year of completion of Degree      2003
5.       Abstract of Thesis

        Surveys conducted in different Lilium growing areas of Solan, Shimla, Mandi,
Kullu and Kangra districts of Himachal Pradesh during the cropping season of 2002
revealed the incidence of virus diseases between 15 and 95 per cent in different localities.
The symptoms evoked by the virus isolate were mild mottling, curling and necrosis of
leaves; deformation and virescence of floral buds and flowers and reduction in bulb size.
The virus isolate was transmissible through sap, bulb and aphid vectors Myzus persicae,
Aphis craccivora and Brevicoryne brassicae. The isolate infected members of the
families Chenopodiaceae, Liliaceae and Solanaceae. Electron microscopic studies of the
virus isolate revealed the presence of filamentous flexuous virus particles measuring 640
x 17-18 mm in size. Results obtained in direct DAS-ELISA revealed that the virus isolate
was lily symptomless carlavirus. Indirect DAC-ELISA tests revealed that the isolate was
serologically related to chrysanthemum B carlavirus and carnation latent carlavirus. The
studies also revealed that Lilium and Alstroemeria were the best maintenance hosts for
the virus isolate. It was concluded that the virus isolate is lily symptomless carlavirus, a
member of the genus carlavirus.
1.       Name of the student and         Varsha Bhardwaj (H-2002-29-M)
         Admission No.
2.       Name of Major Advisor           Dr. Anil Handa
3.       Title of Thesis                 Studies on the production of lily symptomless
                                         carlavirus free ornamental lily hybrid through
                                         meristem tip culture
4.       Year of completion of Degree    2004
5.       Abstract of Thesis

        Studies were undertaken to produce lily symptomless carlavirus free Lilium cv.
Alliance through meristem tip culture. Explants (bulbscales) drawn from lily
symptomless carlavirus infected plants were used for producing bulblets under in vitro
conditions which were subsequently used for obtaining meristems. Results pertaining to
establishment and bulblet multiplication of Lilium cv. Alliance in vitro revealed that MS
medium supplemented with 2 mg 1-1 NAA and 2 mg 1-1 BAP was best in promoting
bulblet multiplication. Meristem tips of 0.5 mm size had a better regenerative capacity
and were capable of producing plants free from lily symptomless carlavirus infection.
Meristem tips were best established on half strength solidified medium supplemented
with 1mg 1-1 NAA and 1mg 1-1BAP. Bulblet multiplication in vitro in Lilium cv.
Aliance was found to be the best on MS medium containing 2 mg 1-1 NAA and 5 mg 1-1
2-iP. MS medium supplemented with 9 per cent sucrose was found to be best for
producing maximum number of bulblets and scales. It was observed that a combination
of 9 per cent sucrose, 0.25 per cent gelrite and 2 mg 1-1agar was the best for producing
maximum number of bulblets and scales. Studies conducted on rooting in vitro revealed
that MS medium supplemented with 1 mg 1-1NAA and 1 mg 1-1IBA produced a higher
number of roots with maximum rot length.
1.       Name of the student and          Sandeep Kumar (H-2001-40-M)
         Admission No.
2.       Name of Major Advisor            Dr. A. K. Gupta
3.       Title of Thesis                  Studies on crown gall of stone fruits
4.       Year of completion of Degree     2004
5.       Abstract of Thesis

         Agrobacterium tumefaciens was the causative agent of crown gall in stone fruits.
Hundred per cent incidence of crown gall was observed in peach seedlings at Palsehar in
district Mandi, Himachal Pradesh. Crown gall infected peach plants showed reduction in
growth, maximum in shoot length (26.60 %). All the isolates of A. tumefaciens from galls
of infected plants and infested soil belonged to biovar-1. Amongst different rhizosphere
micro-flora from healthy and crown gall infected plants, application of Pseudomonas
fluorescens and Bacillus sp. as soil drench (4l/m2 containing 108 CFU-ml) provided 100
and 86.74 per cent control of crown gall in peach. Mustard cake @ 1.5 per cent and pre-
plant treatment of infested soil with formaldehyde (5 %) reduced the incidence of crown
gall to 10.23 and 5.39 per cent, as compared to control (31.80 and 30.07 %), respectively.
Among different antibacterial compounds, copper sulphate (1%) applied as soil drench
also resulted in less incidence (16.79 %) as compared to control (27.50 %).
1.       Name of the student and           Monica Sharma (H-2001-38-M)
         Admission No.
2.       Name of Major Advisor             Dr. S.K.Gupta
3.       Title of Thesis                   Management of root rot and web blight
                                           (Rhizoctonia solani Kuhn) of French bean
                                           through eco-friendly methods
4.       Year of completion of Degree      2004
5.       Abstract of Thesis

        Rhizoctonia solani Kuhn is a polyphagous fungus and has lethal pathogenic
potential of causing different types of disease symptoms. Forty- five isolates collected
from different hosts and locations of north India showed slight variation in
morphological, cultural characteristics and pathogenicity. Molecular markers like RAPD,
microsatellites (ISSR and URPs) grouped the selected 24 isolates into four groups
depending upon host and geographical regions. Line ET 8396 showed resistant reaction
against the disease under natural epiphytotic conditions. Soil solarization (SS) of infested
soil with single and double polyethylene mulch (25 µm) and single polyethylene mulch
along with soil amendment (mustard cake and FYM) resulted in rise in soil temperature
upto 8.6oC at 5 cm depth in double polyethylene mulch. Mulching for 30 and 50 days
eliminated the pathogen from 5 and 10 cm soil depth, respectively. In vitro evaluation of
antagonists revealed that Bacillus subtilis caused 56.08 per cent inhibition of R. solani
followed by Trichoderma longibrachiatum (38.42%) and T. harzianum (32.78%). Under
glasshouse conditions, seed treatment (ST) and soil application of B. subtilis reduced pre-
and post-emergence root rot to 8.33 and 16.60 per cent, respectively, and also resulted in
increased plant height and number of nodules/ plant. Ethanol extract of plants were found
more effective than water and acetone extracts against the pathogen. Ethanol extracts of
Ocimum sanctum and Allium sativum (4%) were found highly effective in inhibiting the
mycelial growth and sclerotial formation under in vitro conditions. Seed dip for 2 h in 4
per cent ethanol extracts of A. sativum and O. sanctum was found effective in checking
the pre- and post-emergence root rot while foliar sprays (2%) were effective in checking
web blight and resulted in increased plant height, number of nodules/ plant and leaf area.
In the field experiments, A. sativum and O. sanctum seed dip was found effective in
checking root rot and web blight. SS + soil amendment + combination of A. sativum and
B. subtilis (ST) was found most effective in reducing pre- and post-emergence root rot
while web blight was best contained by SS + soil amendment + A. sativum (ST+ FS)
followed by SS + soil amendment + combination of A. sativum and B. subtilis (ST) +
Bavistin (0.1%) foliar sprays and increased green pod yields.
1.       Name of the student and          Suneel Anand (H-2001-41-M)
         Admission No.
2.       Name of Major Advisor            Dr. H.R.Gautam
3.       Title of Thesis                  Soil solarization as a component in integrated
                                          management of Fusarium yellows of gladiolus
4.       Year of completion of Degree     2004
5.       Abstract of Thesis

        The field surveys conducted during 2002-2003 revealed that the disease was
prevalent in sub-mountainous regions of the state. All the isolates of Fusarium
oxysporum f.sp. gladioli collected from various parts of the state were found pathogenic
and the isolate from Nauni was found most pathogenic. Among nine fungicides tested
against the pathogen in vitro, combi-product of carbendazim + iprodione (Quintal)
registered maximum inhibition of the pathogen followed by Companion (carbendazim +
mancozeb). The former was also proved most effective under field conditions. All the
Trichoderma spp. tested in vitro inhibited the fungal growth and among them, T. viride
gave the maximum inhibition of the pathogen. Soil solarization for 40 days raised the soil
temperature by 11.0 and 9.0oC over unsolarized plots during 2002 and 2003, respectively
and resulted in 84.6 per cent reduction in viable colony forming units of pathogens at 5
cm soil depth. Soil solarization in combination with cabbage leaf residues reduced the
mycelial growth of the mycelium by 55.2 per cent at 5 cm soil depth. Soil amendment
with cabbage leaf residues followed by solarization for 40 days completely eliminated the
pathogens from upper 5 cm soil layer. Soil amendment with cabbage leaf residue
followed by solarization for 40 days resulted in 98.5 per cent disease control followed by
combination product of carbendazim + iprodione (Quintal). The former treatment also
recorded an increase of 48.5, 51.0, 33.8, 85.8 and 105.8 per cent in shoot length, spike
length, corm size, corm weight and number of cormels per plant. Whereas number of
days taken to first flowering were reduced by 23.1 per cent.
1.       Name of the student and           Pankaj Kumar (H-2001-39-M)
         Admission No.
2.       Name of Major Advisor             Dr. J.N.Sharma
3.       Title of Thesis                   Studies on Marssonina blotch (Marssonina
                                           coronaria (Ell. et J.J.) J.J. Davis) causing
                                           premature leaf fall in apple and its control
4.       Year of completion of Degree      2004
5.       Abstract of Thesis

         The appearance of Marssonina blotch caused by Marssonina coronaria ((Ell. et
J.J. Davis) J.J.Davis) in apple has been relatively a threat to its successful cultivation in
the state. The present studies were conducted on various aspects of the disease and the
pathogenic fungus. Survey of apple growing areas revealed the prevalence of the disease
in all the orchards in moderate to severe form. Light and electron microscopic studies
revealed the identity of the pathogen as Marssonina coronaria as typical Marssonina type
conidia and micro-conidia were found associated with disease tissues. Symptoms of the
disease initially occurred as dark green circular patches, which turned to brown to dark
brown lesions forming large blotches in later stage leading to premature defoliation.
Pathogenicity tests conducted on one year old potted Starking Delicious plants by
artificially inoculating them with standardized conidial suspension produced typical
disease symptoms after 12days of inoculation. Physiological studies revealed that the
fungus grew best in minimal salts medium, at a temperature of 20 oC and pH 5.0. Maltose
and methionine were the best carbon and nitrogen sources for its vegetative growth,
respectively. The pathogen survived in infected over-wintered apple leaves in the form
of conidia under natural conditions and no sexual stage of the fungus was intercepted. A
temperature of 20oC and 100 per cent relative humidity were optimum for the conidial
germination. A minimum of 6 h of leaf wetness duration was required for the initiation of
infection of M. coronaria on older leaves, whereas on younger leaves, duration of atleast
18 h leaf wetness was essential for the disease development. Spartan, K1R46A41 and
P42R37A52 were found moderately resistant to the disease, while all other commercial
Delicious cultivars were susceptible. Among different systemic and non-systemic
fungicides, dithianon and mancozeb gave the maximum inhibition of conidial
germination. In the field trials, propineb, carbendazim + mancozeb, mancozeb, dodine,
dithianon and zineb were found the most effective. A fungicidal spray schedule
comprising of mancozeb (0.3%), carbendazim (0.05%), mancozeb (0.3%) and mancozeb
(0.3%) sprays at pea size, walnut size, fruit development and preharvest stages of apple,
respectively was found effective in controlling the disease.
1.       Name of the student and          Swarn Singh (H-2001-42-M)
         Admission No.
2.       Name of Major Advisor            Dr. S.K.Sharma
3.       Title of Thesis                  Role of Ampelomyces quisqualis        in the
                                          management of powdery mildew of apple
4.       Year of completion of Degree     2004
5.       Abstract of Thesis

        Apple powdery mildew caused by Podosphaera leucotricha (Ell. and Ev.) Salm.
was found to be prevalent in all the apple nurseries of the state. Infected foliage become
crinkled, curled and led to defoliation. The fungal hyper-parasite parasitizing powdery
mildew leaves were isolated and identified on the basis of morphological characters with
the help of taxonomic key. Mycelial diametric growth and dry weight of A. quisqualis
was maximum (35.10mm and 336.00 mg), respectively, on Richard’s medium after 7
days of incubation. Potato dextrose, Waksman’ and Rechards medium supported
excellent sporulation. Among liquid media tested, mycelial growth was maximum on
Rechards’ medium and was taken as basal medium for the subsequent physiological
studies. The hyper-parasite A. quisqualis could grow under wide range of temperature
from 10-35oC. Maximum dry mycelial dry weight (476.20 mg) was recorded at 25oC
followed by 20oC. Maximum mycelial growth (675.20 mg) and sporulation was obtained
at pH6.5 and glucose was observed to be best source of carbon with 595.00 mg of
mycelial growth. Among the different fungicides tested under in vitro, dinocap was least
effective giving 65.66 per cent growth inhibition of A. quisqualis followed by mancozeb
(66.67%). Carbendazim on the other hand gave maximum (90.67%) growth inhibition of
test fungus. Maximum conidial germination and germ tube length was observed in
mancozeb (44.60% and 6.36 µm) and was minimum in case of carbendazim (19.12% and
2.77 µm). In pot experiments, carbendazim at 750 ppm proved to be the most effective
giving 90.14 per cent disease control. While testing the effectiveness of different
fungicides under field conditions, carbendazim (89.38%), hexaconazole (84.21%) and
dinocap (75.29%) provided excellent control of powdery mildew. A. quisqualis inhibited
the conidial germination of P.leucotricha at all the concentrations used, however,
maximum inhibition (67%) was observed at 106 spores/ml concentration. Antagonistic
effect of A. quisqualis was also seen on the growth inhibition of P. leucotricha on
detached leaves under in vitro conditions. Maximum growth inhibition (68.60%) was
observed in case of 106 spores concentration/ml of A. quisqualis followed by 105 spore
concentration/ml (66.52%). The antagonistic effect of A. quisqualis against P. leucotricha
was further assessed under field conditions. the minimum disease incidence (29.44%) and
maximum disease control (70.07%) was observed at 106 spores/ml concentration after 30
days of spray of hyper-parasite. With the increase in the spore concentration/ml of hyper-
parasite there was significant increase in the per cent disease control.
1.       Name of the student and          Ashok Kumar Soni (H-2003-27-M)
         Admission No.
2.       Name of Major Advisor            Dr. H.R.Gautam
3.       Title of Thesis                  Integration of soil solarization with biological
                                          and cultural methods for the management of
                                          Fusarium yellows of gladiolus
4.       Year of completion of Degree     2005
5.       Abstract of Thesis

        The present studies on Fusarium yellows of gladiolus caused by Fusarium
oxysporum f.sp. gladioli Snyd. & Hans. were conducted in the laboratories and
experimental farm of the department. The field survey conducted during 2004 revealed
the prevalence of disease in sub-mountainous regions of the state. Soil solarization in
combination with leaf residues of cabbage, sarson and Chinese sarson reduced the
mycelial growth of the wilt pathogen by 87.5 per cent at 5 cm soil depth. Among seven
botanical extracts tested against the wilt pathogen in vitro, leaf extract of aonla (100%)
was found most effective with 72.8 per cent mycelial inhibition, while among three neem
formulations, Neemazal at 25 per cent concentration completely inhibited the mycelial
growth of the pathogen. All the antagonists tested in vitro, inhibited the fungal growth
and among them, Trichoderma viride gave the maximum inhibition of 62.1 per cent in
the mycelial growth of the wilt pathogen. Soil solarization with transparent polyethylene
mulch (25 µm) for 40 days increased the sol temperature by 8.3 oC at 5 cm soil depth over
the unsolarized plots and reduced the pathogenic potential of the pathogen substantially
i.e. the incubation period increased by 59.8 per cent and the disease incidence was
reduced by 82.1 per cent. The compost of the cabbage leaves was found most effective
with 83.0 and 75.0 per cent reduction in the viable propagule of the pathogen in solarized
plots at 5 cm soil depth after 40 days. Soil amendment of cabbage compost in solarized
soil followed by sowing Pseudomonas fluorescens treated corms was found most
effective in reducing the disease by 85.6 per cent followed by treatment of cabbage
compost along in solarized soil. The former treatment also recorded an increase of 41.7,
46.5, 124.1, 103.6, 47.4 and 59.1 per cent in plant height, spike length, number of florets
per spike, number of cormels per corm, corm size and corm weight, respectively and
number of days taken to first flowering were also reduced by 21.1 per cent.
1.       Name of the student and          Ashwani Singh Chauhan (H-2002-25-M)
         Admission No.
2.       Name of Major Advisor            Dr. S.K.Sharma
3.       Title of Thesis                  Studies on powdery mildew in apple in nurseries
4.       Year of completion of Degree     2005
5.       Abstract of Thesis

        Powdery mildew of apple was found prevalent in moderate to severe form in
Solan, Shimla and Kullu districts of Himachal Pradesh. Incidence of disease ranged from
27.47 to 75 per cent and severity from 22.77 to 60.00 per cent. The characteristic
symptoms consisted of small whitish felt like patches of fungal structures on the leaves
and stems. Severe infection on leaves lead to accelerated senescence with leaves
becoming brown and finally dries up leading to severe defoliation. Microscopic
examination of diseased samples showed presence of typical anamorphs of the pathogen
unbranched conidiophores, truncate conidia arranged in long chains, in basipetal
succession, simple germtubes and presence of one ascus in each perithecium and single
celled, hyaline subglobse ascospores establish the involvement of Podosphesa
leucotricha) as causal agent of the disease. Detached leaves were found more susceptible
to the disease with incubation period of 8 days as compared to leaves of potted seedlings.
Temperature (25oC) and relative humidity (95.60%) showed maximum conidial
germination and germtube length of the fungus. Environmental factors i.e. mean air
temperature, relative humidity and quantitative rainfall influence the powdery mildew
development. Out of 113 cultivars, four showed highly resistant reaction while rest of the
cultivars/lines exhibited moderately susceptible to highly susceptible reactions. In vitro
evaluation of fungicides showed Karathane, Score and Bavistin to be the best and
inhibited the conidial germination and germtube length. Post symptom antisporulant
activity of fungicides against the pathogen revealed that Karathane, Glow and Contaf had
higher degree of antisporulant activity for a longer period (upto 10 days). In the field,
Karathane, Score, Contaf, Sulphur and glow found to be most effective in reducing the
disease incidence as well as severity of the disease. Four sprays of either fungicide were
proved to be better than three and two sprays of the fungicides.
1.       Name of the student and         Amit Kumar (H-2003-26-M)
         Admission No.
2.       Name of Major Advisor           Dr. S.K.Gupta
3.       Title of Thesis                 Role of abiotic environmental factors in the
                                         development of pea powdery mildew (Erysiphe
                                         pisi) and its management
4.       Year of completion of Degree    2005
5.       Abstract of Thesis

        Powdery mildew (Erysiphe pisi D.C.) is an important disease of pea in Himachal
Pradesh. Present investigations were undertaken with an objective to study the role of
abiotic environmental factors in disease development and devise ecofriendly strategies
for its management. Temperature of 25oC and 70.4 per cent relative humidity (RH)
showed maximum conidial germination while germtube length was maximum at 25oC
temperature and 100 per cent RH. Moderate temperature (18.5-23.5oC) coupled with
moderate RH (41.51%) favoured disease development. Eleven pea lines like K-18, K-1,
CHPMR-2, BPH-19, JI-1210, PMR-4, 1543, 381864, JI-1412, K-6, NC-16076 were
found completely disease free while six cvs./lines VRPMR-9, CHP-2, EC-160769,
VRPMR-1, Solan Nirog and Palam Priya were observed as resistant. Cultural practices
like alteration of date of sowing and wider plant spacing were found effective to reduce
the severity of the disease, thereby, suggesting their relevance for inclusion in the
ecofriendly management of this disease. Ethanol extracts of Acorus calamus (1.0%)
resulted in maximum inhibition of conidial germination and germtube length under in
vitro conditions. among commercial formulations of botanicals, Pongamia oil caused
maximum inhibition of conidial germination and germtube length elongation. In field
experiments, foliar sprays of ethanol extracts Urtica dioica (2%) registered minimum
disease severity and maximum green pod yield. K2HPLO4 (1%) sprays resulted in
minimum disease severity and maximum green pod yield. Under in vitro conditions,
wettable sulphur was most effective in reducing the conidial germination and germtube
length followed by kresoxim methyl. In the field experiments, kresoxim methyl and
azoxystrobin were effective in checking the powdery mildew severity and increased
yield. Seed treatment with Rhizobium leguminosarum + Bacillus subtilis + carbendazim
integrated with alternate foliar sprays of diniconazole, Urtica dioica and diniconazole
was found most effective in containing the disease severity and increasing the green pod
yield.
1.       Name of the student and          Ravinder Kumar (H-2002-28-M)
         Admission No.
2.       Name of Major Advisor            Dr. J.N.Sharma
3.       Title of Thesis                  Studies on leaf spot diseases of apple and their
                                          management
4.       Year of completion of Degree     2005
5.       Abstract of Thesis

         In Himachal Pradesh, there has been an increase in the incidence of leaf spotting
diseases in apple. Keeping in view the importance of Alternaria leaf spot, a detailed study
was undertaken with regards to its pathogenicity, physiology, epidemiology, germplasm
screening and management. disease survey revealed the prevalence of different fungal
leaf spots in apple in H.P. Out of two isolates of Alternaria alternata, isolate 2 was more
aggressive. Typical disease symptoms were produced on one year old Royal Delicious
apple seedlings after 3 days of inoculation. Physiological studies included media
selection, effect of temperature, carbon and nitrogen sources. A minimum of 6 hours of
leaf wetness duration was required at 15-25oC for disease initiation. Among different
environmental parameters, relative humidity was directly correlated with the disease
development in the field. Red Gold, Gala Selection, Red Fuji and Golden Delicious wre
found fairly resistant to Alternaria leaf spot of apple. EBI fungicides hexaconazole,
difenoconazole and myclobutanil provided 100 per cent inhibition of spore germination
in Alternaria alternata. A spray schedule comprising the sprays of dodine, carbendazim,
hexaconazole + mancozeb and tebuconazole at different stages during growing season of
apple was highly effective in controlling the disease with 99.21 per cent disease control
in the field.
1.       Name of the student and          Ramal Kumar (H-2002-26-M)
         Admission No.
2.       Name of Major Advisor            Dr. (Mrs.) Sunita Chandel
3.       Title of Thesis                  Management of Fusarium wilt of carnation
                                          through non-chemical methods
4.       Year of completion of Degree     2005
5.       Abstract of Thesis

        During the course of present investigations, different non-chemical methods for
the management of Fusarium wilt of carnation were studied. The soil samples were
collected from four different locations from the rhizosphere of carnation and isolation of
micro-organisms were done. Out of 13 antagonists, Trichoderma species proved to be
most potential antagonistic against F. oxysporum f.sp. dianthi. Out of thirteen plant
extracts tested against F. oxysporum f.sp. dianthi under in vitro for their antagonistic
activity, three plant extracts viz., Allium sativum, Tegetes erecta and Ocimum sanctum
gave more than 70 per cent inhibition mycelial growth of test fungus. Achook and
Nimbicidine, amongst different neem formulations checked disease incidence to more
than 60 per cent. In combined effect of plant extracts and neem formulations, Achook in
combination with Allium sativum and Azadirachta indica gave maximum disease
reduction followed by Nimbicidine with same combinations. Neem cake and pine needles
were found most suitable amongst different organic amendment to manage the disease.
Solarization of soil for two consecutive months (April and May) gave good results with
regard to minimization of wilt disease. Solarized soil reduced the disease and pathogen
population drastically by giving more than 60 per cent disease control as compared to
unsolarized soil. Different antagonists when applied in solarized soil enhanced their
antagonistic activity. In solarized soil, Trichoderma harzianum and T. viride along and in
combination gave maximum reduction of Fusarium wilt of carnation and also enhanced
the plant growth parameters.
1.       Name of the student and          Nguyen Duc Cuong (H-2003-29-M)
         Admission No.
2.       Name of Major Advisor            Dr. N.P.Dohroo
3.       Title of Thesis                  Studies on Sclerotinia rot of cauliflower and its
                                          management through eco-friendly approaches
4.       Year of completion of Degree     2005
5.       Abstract of Thesis

         The field survey during crop season of 2004-05 revealed that the disease was
more severe in sub-mountainous region of the state. Young leaves of cauliflower were
found most susceptible to Sclerotinia rot. The inoculum dose of 250 mg growth
media/plant in soil was found most suitable for disease development. The fungus
produced aerial mycelium, which was hyaline consisting of closely septate hypahe and
measured 2.0-9.4 µm. Micro-conidia were produced on conidiophores of the vegetative
mycelium and measured 1.5 – 3.5 µm. Scleortia were black in colour, round to irregular
and measured 2-15 c 1.5-7 mm. Apothecia were round or globate type with diameter
ranging from 2-9 mm. The asci were hyaline and cylindrical and measured 91-165 x 4.9-
8.5 µm. Ascospores were elliptical and ranged from 6.5-13 x 4.2-6.6 µm. the fungus was
found to grow best on potato dextrose agar medium and Richard solution, respectively.
Optimum temperature and pH for the growth of fungus were 20-25oC and pH 5.0,
respectively. A positive correlation between edaphic factors viz., soil temperature and
soil moisture with disease development was observed. High soil moisture (25%) and low
soil temperature (14.78oC) were found to favour the disease development. Among
botanical extracts and plant derived product tested against the Sclerotinia pathogen under
in vitro conditions, garlic extract and Nemazal were found to completely inhibit the
growth of pathogen. Trichoderma harzianum gave the maximum inhibition (63.26%) of
mycelial growth of the pathogen with prominent inhibition zone (4.17 mm). Under field
conditions, application of Nemazal and T. harzianum had a significant effect on reduction
in disease incidence to 30.49 and 40.62 per cent, respectively in comparison to the
control (55.77%). The screening of varieties of cauliflower against S. sclerotiorum under
artificial epiphytotic conditions indicated the cauliflower DC-76 was disease resistant.