Citrus Thrips Control with DDT investigated in two Coachella

Document Sample
Citrus Thrips Control with DDT investigated in two Coachella Powered By Docstoc
					Citrus Thrips Control with DDT
         investigated in two Coachella Valley groves
                                                                                                                                -                                        W. H. Ewart

RESULTS
      OBTAINED in the Coachella Val-                                                                                                trees in this grove were 25 to 30 feet high
ley with DDT for the control of citrus
                                                Fruits Scarred                                                                      and beyond the reach of the equipment
thrips indicated that DDT gave poorer              A greater percentage of fruits was                                               used.
control than standard nicotine-sugar            scarred in the tops of the trees than at
sprays.                                         lower levels, in all plots treated with the                                         Additions to DDT
   In those initial experiments, conducted      spray-duster, as well as in the untreated
in 1944 and 1945, two pounds of DDT per         plots. More top fruits were scarred than                                              The addition of sulfur or sugar to the
acre were applied with a spray-duster, as       lower fruits in plots in which nicotine-                                            DDT sprays did not materially increase
a 205%DDT wettable powder suspension            sugar was applied with a regular spray                                              their effectiveness. Eight pounds of 50%
in 100 gallons of water.                        rig.                                                                                DDT wettable powder per 100 gallons
   The results were in striking contrast           When DDT was applied with a regular                                              appeared to be nearly as effective as 20
to those obtained in the San Joaquin            spray rig, fruit scarring was prevented in                                          pounds.
Valley, where a similar application of          the tops of the trees as well as at lower                                             In the second experiment, comparisons
DDT on oranges, gave much better con-           levels.                                                                             were made between various nicotine prep-
trol than standard nicotine-sugar sprays.          I t is apparent that DDT was much more                                           arations and DDT. The results showed
   This indicated that under the higher         effective than nicotine-sugar in this par-                                          that Black Leaf 155 was superior to Black
temperature conditions in the Coachella         ticular grove.                                                                      Leaf Dry Concentrate.
Valley, DDT did not have the same effec-           Since the top fruits were scarred in                                               The addition of a small amount of DDT
tiveness as in the San Joaquin Valley.          plots in which DDT was applied with a                                               wettable powder to either Black Leaf 155
   Higher dosages of DDT were tested in         spray-duster it is indicated that the tops                                          or Black Leaf Dry Concentrate did not
1946 in two groves in the Coachella Val-        of the trees were not satisfactorily covered.                                       increase their effectiveness.
ley. In the first grove nicotine-sugar had      This is understandable since many of the                                                                Continued on page 16
given poor results the previous year,
while in the second grove, excellent thrips     COMPARISON OF DDT AND NICOTINE FOR THE CONTROL OF CITRUS THRIPS.
control had been obtained.                               APPLICATION APRIL 22,1946, WITH SPRAY-DUSTER AT
   Applications were made in the first                           RATE OF 100 QALLONS PER ACRE
grove on April 8 and April 16. Fruit
scarring records were made in all plots                                                       Treatment                                                   Amounts per     'er cent of outside
on outside fruits that could be examined                                                                                                                   100 gallons      fruits scarred
                                                                                                                                                                                          -
from the ground level. In some plots, the
fruits in the tops of trees were examined.      Black Leaf 155
   Results showed that DDT was superior           (14~~n ic otin e ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
                                                                           ...                                                                               7 lbs.            ....
                                                Sugar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .        4 lbs.              4.4
to nicotine-sugar sprays when at least
four pounds of actual DDT-eight pounds
                                                Black Leaf 155
of 50% DDT wettable powder-were ap-
plied per acre.
                                                                               +
                                                  (12% nicotine) 7% DDT. . . . . . . . . . . . . . . . . . . . . . . . . . .                                 7 lbs.            ....
                                                Sugar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .            4 lbs.              2.6
   Where the DDT was dissolved in kero-
sene, and applied as an emulsion, the           Black Leaf Dry Concentrate
control was not so good as with DDT wet-          (14% nicotine). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .                  7 lbs.            ....
table powder suspensions.                       Sugar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .          4 lbs.            23.9

Comparisons Made                                Black Leaf Dry Concentrate
                                                  (12% nicotine) + 7% DDT. . . . . . . . . . . . . . . . . . . . . . . . . .                                 7 lbs.            ....
   Two applications of Black Leaf 40-           Sugar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .        4 lbs.            23.7
sugar gave no increase in effectiveness
over a single application. Black Leaf 155       Black Leaf Dry Concentrate
appeared to be slightly less effective than                                    +
                                                  (12% nicotine) benzene hexachloride (3% gamma). . .                                                        7 lbs.            ....
Black Leaf 40, when applied with a spray-       Sugar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .        4 lbs.            28.5
duster. When Black Leaf 155-sugar, or
DDT wettable powder suspensions, were           50% DDT wettable powder.. . . . . . . . . . . . . . . . . . . . . . . . . .                                  8 Ibs.             2.1
applied with a regular spray rig at the rate
of 1000 gallons per acre, using ground          50% DDT wettable powder.. . . . . . . . . . . . . . . . . . . . . . . . . . . .                              8 lbs.            ....
and tower guns, the results were superior       Sugar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .        4 lbs.              1.7
to spray-duster applications, particularly
in the tops of the trees.                       50% DDT wettable powder.. . . . . . . . . . . . .                                                           20 lbs.             0.2
   Applications of insecticides, with a
regular spray rig, for thrips control           4.8% DDT in kerosene solution + emulsifier.. . . . . . . . . . . . .                                         5 gals.            9.3
would be of doubtful practical value be-
cause of the much greater cost as com-          Untreated check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .               ......             40.4
pared to spray-duster applications.

CALI F 0 R N I A AG R I C U L T U R E, F E B R U A R Y, 194 8                                                                                                                            11
                 MEALYBUG                          Resealed Graft Clefts
              (:illit iriiivtl   from page 9      When a graft cleft seal is clacked, it
 covered with a hag and 15 were found          is the piactice to reseal the cleft. Any                                    NEW PU                                                 NS
 on the scions which were uncovered, hut       insecticide applied before the second ap-
 shaded with a parasol, again indicating       plication of sealing substance is the1 ehy
 n o adcantape to the niealyhugs o n the       covered over. In the experiment referred BEEKEEPIKG I N CALIFORNIA, b). J .
 scions wvered with a bag.                     to above, it was learned that on the trees E. Eckert. Ext. Cir. 100, revised Decent-
    A t the conclusion of the experinletit     o n which the mealybugs were seen, the her, 1947. ( 9 6 pages ) .
 made in the Encinitas orchard? the dust       grafting cleft had been resealed with a
 treatment was wntinued on the dusted                                                      THE COMMERCIAL FREEZING 0 .           1’
                                               substance used for that purpose but not FRUIT PRODUCTS, b y M . A . Joslytr
trees, and: of the other six trees, three      repainted with the insecticide. This made and Leonora A . Hohl. Bul. 70.3, January,
were painted with a slurry made with           a “bridge” for the mealybugs and ants to 1948. ( 1 0 8 p a g e s ) .
50:; wettable 1 ) D T .powder, and three       irestablish connections with the scions.
 were painted with a slurry made of a wet-        In this orchard, as well as in all the COST OF ALMOND PRODUCTION l A
table powder containing 10‘& of the            other orchards in which experiments were CALIFORNIA, b y R . L. Adams and A .
gamma isomer of benzene hexachloride.          made, i t was only 011 trees on which the D . Reed. Cir. 375, January, 1948. ( 2 2
    The slurries contained one ounce of        graft clefts were resealed after the appli- pages ) *
powder t o 100 cubic centimeters of water.
                                               cation of the insecticide that it was
They were applied with a paint brush to
                                               possible for the mealybugs to become es- HOME ECONOMICS AT THE L’NI-
the tops o f the grafted stumps and three                                                  VERSITY OF CALIFORNIA, b y the De-
                                               tablished.
or four inches below the top.                                                              partments of Home Economics at Berke-
    The treatments were applied on April          When graft clefts are resealed, the in-
28, 1917, and observations were made on        secticide should be reapplied on the af- ley, Davis, Los Angeles, and Santa Bar-
                                               ferted trees.
                                                                                           bara. Brochure. (18 p a g e s ) .
May 21, 1947. On that date, one of the
trees treated with DDT dust had 17 mealy-                                                                                SOILS OF A PORTION OF P A L 0
                                                  Walter Ebeling is Lecturer in Entomology,
bugs on the scions and one of the trees        arid Associate Entomologist in the Experiment                             VERDE VALLEY (Between the Levee
treated with the DDT slurry had 10 mealy-      Station, Los Angeles.                                                     and the R i v e r ) , b y Walter W . Weir and
bugs. K O mealybugs could be found on             Roy J. Pence is Principal Laboratory Techni-                           R . Earl Storie. Lithoprinled, August,
any of the other trees.                        cicrn, 1)ieision of Entomology, 1’0s Angeles.                             1947. ( 1 4 p a g e s ) .


             CITRUS THRIPS                     until more information is developed on                                    have failed to give satisfactory control,
             Continued from page 11            the length of time DDT residues will kill                                 growers may wish to apply DDT. In such
                                               this beneficial insect, care should be used                               cases, eight pounds of SOY] DDT wettable
   The addition of benzene hexachloride        in applying sprays containing DDT.                                        powder per 100 gallons of water per acre.
to Hack Leaf Dry Concentrate was of no                                                                                   applied with the spray-duster, should be
benefit.                                       Recommendations Limited                                                   used.
   All DDT wettable powder suspensions                                                                                      Further experimental work is under
gave only slightly better control than            Because of the many factors that are                                   way in the Coachella Valley, using DDT
Black Leaf 155-sugar sprays.                   as yet unknown about DDT applications                                     as well as other promising materials.
   This is in contrast to the results ob-      on citrus, it is not recommended for gen-
                                               eral use. should not be applied commer-                                      W . H . Ewart is Assistant Entonlologist in the
tained in the first experiment where DDT                                                                                 Experiment Station, Riverside.
wettable powder sprays were markedly           cially, for the control of thrips, in groves
                                                                                                                           The initial experiments mentioned in the sec-
better than nicotine-sugar sprays. A spray     where nicotine-sugar ’prays have given                                    ond paragraph were conducted by C . 0 .Persing,
containing 20 pounds of SO% DDT wet-           satisfactory results.                                                     then Assistant Entomologist in the Experiment
table powder per 100 gallons gave slightly        In groves where nicotine-sugar sprays                                  Stntion, Riuerside.
better control than one containing eight
pounds. As in the first experiment the
                                                                              DONATIONS FOR AGRICULTURAL RESEARCH
DDT-kerosene emulsion spray was less                       (;ifts   tci                California for research by the College of Agriciiltrire,
                                                                          I lie Ilnivrrsity of
effective than the DDT wettable powder                                                  arrcpted in January, i<)1X
suspension.                                                                                                BERKELEY
                                                    Air Reduction Sales Co                                                                    10 grams dl ethionine RL 471120
                                                                                                 Division of Poultry Husbandry
Vedalia Beetle                                      D o w Chemical Co......................                 .............................   2 quarts Dowklor 40% Emulsifiable
                                                                                                    Division of Entomology
     A fairly large acreage of citrus in the        Stockton State Hospital        .........................................................
                                                                                              Department of Veterinary Science
                                                                                                                                                   Milking cow, Tag No. 1719
Coachella Valley has been treated experi-           Sugar Research Foundation          ...................................................................................   $880.00
mentally with DDT each year since 1944                                                        Division of -Plant Nutrition
and thus far, there has been no abnormal            Swift & C o............................................................................................             $20,000.00
                                                                                          Department of Veterinary Science
increase i n the population of cottony-                                                                       DAVIS
cushion scale, in any of the plots, as a
result of killing off the predacious vedalia
heetle.
                                               I    Canners League of California ...........


                                                    Julius Hyman & Co
                                                                                                    ...........................................................
                                                                      Production of stock seed‘from two improved asparagus strains
                                                                                          Division of Truck Crops
                                                                                                                                                                             S276.33


                                                                                                                                                                         51.250 00
  The plots h a \ e heen widely scattered                                          Investigations of a new insecticide
                                                                                          Division of Entomology
over the c,itrus-growing area so it is not          U S Public Health Service                                                                                            S 1.794 90
possible, at this time, to predict what                                                        Rodent Control
                                                                                             Division of Zoology
might happen if the entire citrus acreage
were treated with DDT.                                                                                 LOS ANGELES
                                                    W Atlee Burpee Co                                                                                                        $50 00
   It is definitely known that the vedalia                                         1947-1948 W. Atlee Burpee Award in Horticulture
beetles are very susceptible to DDT and

16                                                                                            C A L I F O R N I A A G R I C U L T U R E , F E H R tJARY, 1 9 4 8

				
DOCUMENT INFO