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Effects of Azadirachta indica products on the management of Ootheca mutabilis on Telfairia occidentalis in Calabar, Southeast Nigeria
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Effects of Azadirachta indica products on
the management of Ootheca mutabilis on
Telfairia occidentalis in Calabar,
Southeast Nigeria
S.B.A. Umoetoka,
A.N. Osuagwub,
I.A. Udoa,
M.I. Idiongettea,
D.A. Ukeha, c, , ,
a
Department of Crop Science, University of Calabar, PMB 1115 Calabar, Nigeria
b
Genetics and Biotechnology, University of Calabar, PMB 1115 Calabar, Nigeria
c
School of Biological Sciences, University of Aberdeen, Tillydrone Avenue,
Aberdeen AB24 2TZ, United Kingdom
Received 27 November 2008. Revised 26 February 2009. Accepted 2 March
2009. Available online 3 April 2009.
http://dx.doi.org/10.1016/j.cropro.2009.03.002, How to Cite or Link Using DOI
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Abstract
Field experiments were conducted from 2003 to 2006 to evaluate the use of neem,
Azadirachta indica, seed powder and extract and their time and intervals of application in
the management of Ootheca mutabilis on Telfairia occidentalis (Fluted pumpkin) in
Calabar, Cross River State. Seed powder and extract were used as soil drench and foliar
spray at the rates of 20 kg ha−1 and 30 kg ha−1, respectively. The control treatment had no
A. indica application. In the second experiment, 30 kg ha−1 of A. indica seed powder was
soil drenched at seed germination and symptom expression using three intervals (7, 14
and 21 days after germination (DI)). The treatments were arranged as factorial
experiments in a randomised complete block design (RCBD) and replicated three times.
The lowest population of O. mutabilis (1.97 per stand) was observed when 30 kg ha−1 of
the powder was soil drenched as against 3.93 on foliar application and 12.56 on the
control. The interaction was also significant where the lowest population of O. mutabilis
per stand was 1.40 and 1.44 observed when 30 kg ha−1 of each factor was combined. The
percentage defoliation was 3.20% and 2.24% in 2003 and 2004 in plots that received soil
application and 7.32% and 7.38 on the foliarly treated plots, respectively, while 45.98%
and 55.79% defoliation was observed on the control. The highest yield of 4.03 t ha−1 was
observed when A. indica seed powder was applied into the soil. Application of A. indica
seed powder at germination and at 7 days interval (7 DI) resulted in significantly
(P ≤ 0.05) lower population of O. mutabilis (1.69–3.08 per stand) than 7.05–9.61 per
stand that was observed when application was at symptom expression, while the
percentage defoliation was 4.96–8.92 at germination compared to 30.42–41.38 observed
when application was done at symptom expression. Application of A. indica seed powder
at germination and at 7 DI resulted in significantly (P ≤ 0.05) higher harvestable vines
and leaves of 3.29 t ha−1 and 4.01 t ha−1 than 1.37 t ha−1 and 2.21 t ha−1 that was harvested
at symptom expression in 2005 and 2006, respectively. The use of A. indica products in
the management of O. mutabilis is confirmed in this study and should be encouraged
especially for resource poor farmers, this product is easy to obtain and processed with
relatively low toxic effects.
Keywords
Biopesticides;
Azadirachta indica;
Ootheca mutabilis;
Telfairia occidentalis;
Grain yield
1. Introduction
Telfairia occidentialis (Hoof L.) commonly called fluted pumpkin belongs to the family
Cucurbitaceae and is a crop of commercial importance grown across the lowland humid
tropics of Nigeria, Ghana and Sierra Leone (West Africa), and Cameroon (Central
Africa) being the major producers ( [Schippers, 2000] and [Nkang et al., 2003]). It is a
creeping vegetative shrub that spreads low across the ground with large lobed leaves and
long twisting tendrils (Horsfall and Spiff, 2005). The crop is a tropical vine grown mainly
for the leaves which constitute an important component of the diet of many people in
West African countries (Fagbemi et al., 2005) and for its edible seed. The young shoots
and leaves of the plant are the main parts used in soup (Aregheore, 2007). The leaves are
a rich source of protein, oil, vitamins and minerals which enhance, nourish, protect and
heal the body. The green leaves are low in crude fibre, rich source of folic acid, calcium,
zinc, potassium, cobalt, copper, iron, vitamins A, C and K and also have medicinal value
( [Ladeji et al., 1995] and [Ajibade et al., 2006]). Relative to most common vegetables,
its protein content is high ( [Okoli and Mgbeogu, 1983] and [Ladeji et al., 1995]). The
leaf composition per 100 g edible portion is water 86.4 g, energy 147 kJ (47 kcal), protein
2.9 g, fat 1.8 g, carbohydrate 7.0 g, and fibre1.7 g (Grubben and Denton, 2004).
Insect pests constitute a major limiting factor in T. occidentalis production in the tropics
(Williams et al., 1991). The insect pest complex of T. occidentalis include Zonocerus
variegatus, the leaf beetle Copa occidentalis, the flea beetle O. mutabilis, Spodoptera
spp., Nezara spp. (Green shield bug), Aphis gossypii and A. spiraecola most of which
feed on leaves, others on fruits and stems. A. gossypii and A. spiraecola transmit viruses
(Grubben and Denton, 2004). O. mutabilis Sahlberg (Coleoptera: Chrysomelidae) is also
observed to be one of the most common insect pests of T. occidentalis in southeastern
Nigeria (author's and farmers' reports), and cowpea Vigna unguiculata (L. Walp) (Ofuya,
1989). Singh and Rachie (1985) reported much of the damage to field crops by O.
mutabilis and O. bennigseni is caused by the adult feeding between veins in the leaves.
The damage by the insect is more serious on early season plantings, which coincide with
their emergence. These damages include defoliation, deformation and destruction of the
tissues of the leaves, inflorescence and stems by larvae and adults resulting to yield losses
of economic proportions (Ezueh, 1978). There are insecticides which can provide
adequate control of O. mutabilis (Jackai and Daoust, 1986). However, concern for the
environment and the fact that T. occidentalis is cultivated in Africa by resource poor
farmers who seldom use pesticides because of financial and technical limitations
necessitated the need for the application of safer biopesticides.
Research in recent years has been focused on selective biopesticides because they are
generally perceived to be safer than the synthetics (Amason et al., 1989). Among these
biopesticides, Azadirachtin, isolated from the neem tree, Azadirachta indica A. Juss
(Meliaceae), has attracted great attention ( [Schmutterer, 1990] and [Mordue and
Blackwell, 1993]). Azadirachtin stimulates specific deterrent cells in mouthpart
chemoreceptors and also blocks the firing of sugar receptor cells which stimulates
feeding thereby resulting in starvation, and death of insect species ( [Mordue et al.,
1998] and Mordue (Luntz) and Nisbet, 2000). The growing accumulation of literature
also reports that A. indica products work by intervening at several stages of insect's life
(NRC, 1992). Neem extract is a potent repellent, antifeedant, growth regulator and
oviposition deterrent affecting more than 200 species of pests ( [Schmutterer and Singh,
1995] and [Martinez-Villar et al., 2005]). Increasingly, approaches of this kind are seen
as desirable methods of pest control. Neem extracts can be applied in many ways,
including some of the more sophisticated methods. For example, they may be employed
as sprays, powders, drenches or diluents in irrigation water (NRC, 1992).
The objectives of this study were to (i) confirm the damage caused by O. mutabilis to T.
occidentalis (ii) evaluate the efficacy of A. indica seed products in the management of O.
mutabilis and (iii) determine the time and frequency of application of A. indica products
in the management of O. mutabilis.
2. Materials and methods
The experiment was conducted at the Teaching and Research Farm of the University of
Calabar, Cross River State, Nigeria in the late planting seasons. Cross River State lies
between latitude 5°32′ and 4°27′ north and longitude 7°15′ and 9°28′ east. Total annual
rainfall in the area is about 2000 mm–2500 mm. The rainfall pattern is bimodal, with a
long (March–July) and short (August–October) rainy seasons separated by a short period
of dryness in August. The mean annual temperature ranges between 23 °C and 33 °C
while the relative humidity is 60–90% (CRSNMANR, 1989).
2.1. Collection and preparation of samples
Fluted pumpkin seeds were obtained from a local market in Calabar, Nigeria while the
neem fruits were harvested from neem trees planted at the University of Calabar campus.
The fruits were sun-dried and pounded lightly in mortar to release the seeds. The seeds
were further oven-dried at 40 °C for 1 h and ground into powder using a mortar. The
ground seeds were sieved in a 2 mm mesh and kept in a sealed container until needed.
2.2. Experiment 1
This experiment was conducted during 2003 and 2004 late cropping seasons. The study
site was cleared of weeds, packed, stumped and tilled. Twenty-seven plots each
measuring 3 m × 3 m were marked out. Each plot was separated by an alley measuring
1 m. Two seeds of fluted pumpkin were sown per stand at a depth of 2 cm and spacing of
1 m × 1 m. They were later thinned to one seedling to make a population of 10,000
plants ha−1. The treatments were as follows. Neem seed powder at 0, 20 and
30 kg ha−1applied directly into the soil and the same quantities soaked in 400 l of water
for 4 h and the filtrate applied foliarly using a Knapsack sprayer. The control plot had no
neemapplied. Neem seed powder was applied as soil application and neem seed extract as
foliar application. The experiment was arranged in a randomised complete block design
(RCBD) and replicated three times. The plots were hand-weeded at 3 and 8 weeks after
planting. No fertilizer was applied.
2.3. Experiment 2
The second experiment was conducted during 2005 and 2006 late cropping seasons at the
Teaching and Research Farm of the University of Calabar, Calabar, Cross River State.
Neem seed powder (30 kg ha−1) was applied at two different times (i.e. at germination
and at symptom expression) and three frequencies of application (7, 14 and 21 days after
germination) to T. occidentalis. The experiment involved two factor factorial arranged in
a randomised complete block design (RCBD) and replicated three times. All cultural
practices were as reported in the first experiment.
2.4. Data collection and analysis
All data were collected from the two central rows of each plot. The population of O.
mutabilis was counted weekly for 6 weeks by excavating the soil around each plant to the
depth of 2–3 cm and the average was used for analysis. Percentage defoliation was
estimated using the leaf area metre (Delta T. Devices Ltd., Cambridge). Yield
(marketable vines and leaves) of fluted pumpkin was taken by harvesting the young vines
and leaves at 3-week intervals with a sharp knife and later taken to the laboratory and
weighed on an electronic balance (Mettler Instrument AG, Zurich, Switzerland). Data
collected were subjected to the Analysis of Variance (ANOVA) and means separated
using Least Significant difference (LSD) at 5% level of probability.
3. Results
3.1. Experiment 1: effects of soil and foliar application of neem seed
powder and extract on the control of O. mutabilis
3.1.1. The population of O. mutabilis
Effects of neem seed powderapplied into the soil and as foliar spray were significant
(P ≤ 0.05). The treated plots had significantly lower insect pest population than the
control (Table 1). Soil application resulted in lower population of O. mutabilis than foliar
application. The interaction effect was also significant (P ≤ 0.05). The lowest insect pest
population was observed when 30 kg ha−1 of the neempowder and extract were combined
and soil drenched and foliar sprayed.
Table 1. Effects of method of application of neem seed powder and extract on
Ootheca mutabilis population density, percentage defoliation and yield of
Telfairia occidentalis.
Seed extract (kg ha−1 w/v) (foliar
Seed powder (kg ha−1) (soil
Year application) Mean
application)
(a) Population density of Ootheca mutabilis
0 20 30
0 12.56 8.88 6.60 9.35
2003 20 6.00 4.57 3.80 4.79
30 2.60 1.90 1.40 1.97
Mean 7.05 5.12 3.93
0 21.72 13.06 9.22 14.67
20 7.11 5.17 4.50 5.59
2004
30 3.78 2.72 1.44 2.65
Mean 10.87 6.98 5.05
(b) Percentage (%) defoliation of T. occidentalis by Ootheca mutabilis
0 20 30
0 45.98 29.08 14.47 29.84
2003
20 8.37 6.32 4.96 6.55
30 3.67 3.20 2.72 3.20
−1 Seed extract (kg ha−1 w/v) (foliar
Seed powder (kg ha ) (soil
Year application) Mean
application)
Mean 19.34 12.87 7.38
0 55.79 28.31 15.96 33.35
20 8.49 6.79 4.90 6.77
2004
30 2.98 2.65 0.09 2.24
Mean 22.41 12.59 7.32
(c) Yield (t ha−1) of T. occidentalis
0 20 30
0 1.25 1.40 1.50 1.38
2003 20 1.63 2.42 2.61 2.22
30 2.81 2.91 3.21 2.98
Mean 1.90 2.24 2.44
0 1.15 1.30 1.63 1.36
20 2.21 3.12 3.34 2.89
2004
30 3.80 4.01 4.27 4.03
Mean 2.39 2.80 3.08
Population density of O. mutabilis.LSD (0.05) for 2003: soil application = 0.76,
foliar spray = 0.76, soil application × foliar spray = 1.32.LSD (0.05) for 2004: soil
application = 0.99, foliar spray = 0.99, soil application × foliar
spray = 1.71.Percentage (%) defoliation by O. mutabilis.LSD (0.05) for 2003: soil
application = 1.95, foliar spray = 1.95, soil application × foliar spray = 3.37.LSD
(0.05) for 2004: soil application = 1.62, foliar spray = 1.62, soil
application × foliar spray = 2.80.Yield (t ha−1) of T. occidentalis.LSD (0.05) for
2003: soil application = 0.23, foliar spray = 0.23, soil application × foliar
spray = 0.40.LSD (0.05) for 2004: soil application = 0.12, foliar spray = 0.12, soil
application × foliar spray = 0.21.
3.1.2. Percent defoliation
Soil treatment of neem resulted in significantly (P ≤ 0.05) lower percentage defoliation
than foliar spray and the control (Table 1). The interaction was also significant
(P ≤ 0.05). A combination of soil application and foliar spray at 30 kg ha−1 gave the
lowest percentage defoliation. This was followed by plots that had 30 kg ha−1 soil
application combined with 20 kg ha−1 extract foliarapplied.
3.1.3. Yield (harvestable vines and leaves)
The results of application of neem seed powder directly into the soil and by foliar spray
on the yield of fluted pumpkin are presented in Table 1. There was significant (P ≤ 0.05)
increase in yield in the treated plots over the control. Significantly (P ≤ 0.05) higher yield
was obtained in plots that received soil application than plots that were foliar sprayed.
The interaction effect was also significant (P ≤ 0.05). The highest yield was obtained in
plots that received a combination of soil application and foliar spray at 30 kg ha−1neem
seed powder.
3.2. Experiment 2: effects of time and interval of application of neem seed
powder on the control of O. mutabilis
3.2.1. The population of O. mutabilis
The effects of time and frequency of application of neem seed powder are presented in
Table 2. Application at germination resulted in significantly (P ≤ 0.05) lower population
of O. mutabilis than when application was made at symptom expression. The frequency
of application was also significant (P ≤ 0.05). Application at 7 days interval (DI) gave
significantly lower population than when application was done at 21 DI. The interaction
effects indicated that significantly lower population was observed when application was
made either at germination or symptom expression at 7 DI than application at 21 DI.
Table 2. Effects of time and frequency of application of neem seed products on
the population density of Ootheca mutabilis, percentage (%) defoliation and yield
of Telfairia occidentalis.
Frequency of application (days)
Year Time of application Mean
(a) Population density of Ootheca mutabilis
7 14 21
At germination 3.08 3.88 5.01 3.95
2005 Symptom expression 7.05 8.92 10.89 8.95
Mean 5.07 6.40 7.95
At germination 1.69 2.17 6.34 3.40
2006 Symptom expression 9.61 11.80 12.49 11.30
Mean 5.65 6.99 9.42
(b) Percentage (%) defoliation of T. occidentalis by Ootheca mutabilis
At germination 4.96 5.82 7.25 6.01
2005 Symptom expression 41.38 45.36 54.71 47.15
Mean 23.17 25.59 30.96
Frequency of application (days)
Year Time of application Mean
At germination 8.92 9.74 12.66 10.44
2006 Symptom expression 30.42 34.98 60.84 42.08
Mean 19.67 22.36 36.75
(c) Yield (t ha−1) of T. occidentalis
At germination 3.29 2.39 1.98 2.55
2005 Symptom expression 1.37 1.12 0.96 1.15
Mean 2.33 1.76 1.47
At germination 4.01 3.13 2.35 3.16
2006 Symptom expression 2.21 1.35 1.09 1.55
Mean 3.11 2.24 1.72
Population density of O. mutabilis.LSD (0.05) for 2005: Time of
application = 0.41, frequency of application = 0.51, interaction = 0.72.LSD (0.05)
for 2006: time of application = 0.28, frequency of application = 0.35,
interaction = 0.49.Percentage (%) defoliation by O. mutabilis:LSD (0.05) for
2005: time of application = 0.89, frequency of application = 1.09,
interaction = 1.54.LSD (0.05) for 2006: time of application = 0.98, frequency of
application = 1.21, interaction = 1.70.Yield (t ha−1) of T. occidentalis:LSD (0.05)
for 2005: time of application = 0.16, frequency of application = 0.19,
interaction = 0.27.LSD (0.05) for 2006: time of application = 0.09, frequency of
application = 0.11, interaction = 0.16.
3.2.2. Percent defoliation
The effects of neem application at germination and at symptom expression indicated that
significantly (P ≤ 0.05) lower percentage leaf defoliation was observed when application
was made at germination (Table 2). The interaction was also significant. Application of
the neem seed powder at germination and at 7 DI resulted in lower percentage defoliation
than when application was made at 21 DI. No significant (P ≥ 0.05) difference was
observed between 7 and 14 DIs when the product was applied at germination.
3.2.3. Yield (harvestable vines and leaves) of fluted pumpkin
Yield of fluted pumpkin was significantly (P ≤ 0.05) higher on plots that received neem
application at germination, 7 and 14 DIs than when application was made at symptom
expression and at 21 DI (Table 2). The interaction between the time and frequency of
application was significant (P ≤ 0.05) when application was made at germination but not
all combinations were significant (P ≥ 0.05) when application was made at symptom
expression. The highest yield for the two years was obtained when application was done
at germination and 7 DI. The results also indicated that there were significant interaction
(P ≤ 0.05) effects between the time and intervals of application of the neem seed powder
in all the observed parameters. Application at germination and at shorter intervals gave
better control of the insect pest hence reduced the leaf damage on the crop and enhanced
yield of T. occidentalis.
4. Discussion
The insecticidal properties of neem products as reported by many authors ( [Schmutterer,
1990], [NRC, 1992], [Emosairue and Ukeh, 1996] and [Emosairue and Ubana, 1996])
have therefore been confirmed in this study. For example, the low population density of
O. mutabilis observed indicated that the insect pest can be controlled by the use of neem
seed extracts. Field evaluations of the effect of neem products on O. mutabilis of T.
occidentalis indicated that the prevalence of the pest in neem-treated plots was reduced
compared to the untreated plots. Yield differences between neem-treated plots and the
untreated plots were also observed during the study. Good management was achieved
when the powder was applied directly into the soil than foliar application. According to
Ochieng (1977), Ootheca species spend their entire life cycle in the soil especially at the
base of their host making soil incorporation of any i
