, .. July 194,.-\RD E-751
United States Department of Agriculture
Agricultural Research Administration
Bureau of Entomology and Plant Quarantine
TESTS WITH MIST BLOWERS TO CONTROL VARIOUS IfSECTS
By F. Wo Poos, Division of Cereal and Forage Insect Investigations,
S. F. Potts, Division of Forest Insect Investigations, and
L. D. Anderson and J. W. Brooks,!/ Virginia Truck Experiment Station
The tests described herein were conducted during August 1946 in
southeastern Virginia and at Beltsville, Md. The main objective of these
tests was to determine the effective range of the two mist Hloewers used
in applying the various insecticidal formulations to control the insects
involved. Of importance also were the observations on the direct effect
of the formulations on the plants to which they were applied by this
equipment. The 25-hp. mist blower was mounted on al 1/2-ton truck for
these tests. It was described by Potts and FriendY/ and was adapted for
applying dust and concentrated spray formulations, either separately or
both at the same time. The blower delivered about 8,730 cubic feet of
air per minute at an outlet velocity of about 124 miles per hour through
a short cylindrical discharge pipe 12 inches in diameter. The 1 1/2-hp.
portable mist blower, described by Potts and Spencer,2/ was mounted on a
wheelbarrow. This blower delivered 120 cubic feet of air per minute at
240 miles per hour through a nozzle 1 1/4 inches in diameter.
The amount of insecticide applied to a given area by the mist blowers
is indefinite and can only be estimated. All applications to alfalfa and
peanuts with the large mist blower were made from one side of the plot
or field, about 1 gallon of spray being used while the machine traveled
approximately 50 to 75 feet. In one instance 20 pounds of 2-percent DDT
dust was applied to alfalfa while the machine traveled 180 feet along the
side of the field. Larger dosages were usually applied to the corn,
because most of the areas treated were so planted that the insecticides
could be applied from both sides of each plot without damaging the crop
with the machine.
SThe authors are indebted to various specialists in the Division
of Insect Identification for all specific determnninations referred to in
this paper; and to R. A. Spencer, of the Connecticut Agricultural
Experiment Station, for valuable assistance in the mechanical phases of
3/ Potts, S. F., and Friend, R. B. Mist blowers for applying
concentrated spray. Conn. Agr. Expt. Sta. 501: 47-60, illus. 1946.
J/ Potts, S. F., and Spencer, R. A. A small portable mist blower
for applying concentrated spray. U. S. Bur. Ent. and Plant Quar. ET-234,
3 pp. [Processedj 1947.
The following formulations were applied to various crops with the
large mist blower (applied as sprays unless otherwise indicated)s
l. DDT 1 percent, sulfur 91 percent, inert material 8 percent (dust).
2. DDT 2 1/2 pounds, xylene 3 pints, kerosene to make 5 gallons.
3. DDT 1 1/4 pounds, xylene 1 1/4 quarts, kerosene to make 5 gallons.
4. DDT 2 pounds, xylene 2 1/2 quarts, Triton X-100 (aralkyl polyether
alcohol) 5 ounces, plus water to make 4 gallons
5. DDT 2 1/2 pounds, xrlene 3 pints, No. 10 motor oil 8 quarts,
kerosene to make 4 gallons.
6. DDT 3 pounds, xylene 3.6 quarts, kerosene to make 3 gallons.
7. DDT 5 pounds, xylene 6 1/4 quarts, No. 10 motor oil 4 quarts,
kerosene to make 5 gallons.
8. DDT 5 pounds, Vylene 6 1/4 quarts, Triton X-100 12 ounces, water
to make 5 gallons. (Also applied to corn with small mist blower).
9. DDT 5 pounds xylene 6 quarts, Igepal CA (a polyether alcohol
condensate) extra high concentrate 12 ounces, water to make
10. DDT 2 percent in pyrophyllite (dust).
11. DDT 2 pounds, ylene 2 1/2 pints, Vatsol O.T. (dioctyl sodium
sulfosuccinate) 2 ounces, water to make 2 gallons.
12. Lead arsenate (dust).
13. DDT 1 pound, ylene 1 1/4 quarts, Triton X-100 2 ounces, water to
make 6 quarts.
14*. Lead arsenate dust 3 pounds, applied at same time as spray contain-
ing lead arsenate 3 pounds, linseed oil 10 ounces, No. 10 motor
oil 5 ounces, water to make 6 quarts.
15. Lead arsenate dust 6 pounds, applied at same time as spray contain-
ing linseed oil 3 pints, No. 10 motor oil 1/2 pint, Triton X-100
3 ounces, water to make 3 gallons*
16. DDT 8 ounces, xylene 5 pints, kerosene to make 6 quarts*
17. DDT 1 pound, ylene 5 pints, kerosene to make 6 quarts.
18. DDT 2 pounds, ylene 5 pints, kerosene to make 6 quarts; DDT
0.5 pound, pyrophyllite 4*5 pounds applied 3 hours later.
19. DDT 8 ounces, xylene 5 pints, kerosene to make 6 quarts, applied
at same time DDT 0.5 pound, pyrophyllite 4.5 pounds.
20* Lead arsenate dust 6 pounds, applied with spray consisting of
linseed oil 1.2 pints, No. 10 motor oil 0.6 pint, water to make
2L& Lead arsenate dust 6 pounds, applied with spray consisting of
linseed oil 1.5 quarts, No. i0 motor oil 3/4 pint, Triton X-100
3 3/4 ounces, water to make 6 quarts.
22. Benzene hexachloride (10 percent gamma isomer) 10 pounds, linseed
oil 2 pints, No. 10 motor oil 1/2 pint, water to make 3 gallons.
23. Chlordan 8 ounces, kerosene to make 6 quarts.
24.. DDT 2 pounds, xylene 5 pints, kerosene to make 6 quarts,
25. DDT 8 ounces, xylene 1.2 pints, Triton X-100 1 ounce, water to
make 6 quarts.
Tests on Alfalfa and Peanuts
Tests with the large mist blower were conducted primarily to determine
whether insecticidal dust mixtures or atomized concentrated-spray formula-
tions could be applied satisfactorily at distances ranging from 50 to
150 feet from the machine to control the potato leafhopper (Emnpoasca fabae
(Harr.)) on alfalfa and peanuts and the corn earwrm (Heliothis armigera
(Hbn.)) and fall armyworm (Laphygma frugiperda (A, and S.)) on corn. The
atomized concentrated sprays were blown and drifted across the field as
much as 650 feet in one instance, and some kill of the potato leafhopper
on alfalfa was indicated in treated areas at that distance from the
machine. As shown in table 1, satisfactory kill of the potato leafhopper
was generally obtained on alfalfa and peanuts up to 250 feet from the
machine, when emulsions containing as little as 1/4 pound of DDT per gallon
were applied. Acknowledgment is made to E. T. Batten and J. M, Grayson
of the Tidewater Field Station for assistance with the tests on peanuts at
The alfalfa treated at Lynnhaven, Va., to control the potato
leafhopper was also infested with the pea aphid (Macrosiphum pisi (Kltb.)).
Records were therefore made on the effectiveness of the formulations against
the pea aphid, as well as against the potato leafhopper. Results of the
redaction in populations of the pea aphid following the application of
formulas 2, 6, 7, and 8 to alfalfa at Lynnhaven, Va., tabulated in table 2,
indicate that satisfactory kill was obtained 250 to 350 feet from the
machine. Populations of the pea aphid were estimated by making 20 to 75
sweeps of the net in each area treated, the number being the same for each
treatment and its corresponding untreated check. Although the figures
given for each individual test in table 2 are based on an equal number of
sweeps of the net, between tests the number of sweeps ranged from 20 to 75.
Although not clearly apparent from the data given in tables 1 and 2,
it seemed evident as the samples were taken that the insecticides contain-
ing DDT reached their full effect against the potato leafhopper within
24 hours after application, but required a longer time to attain their
full effect against the pea aphid.
It appeared to be impossible to distribute the insecticide uniformly
aver the alfalfa at different distances from the machine, as shown by the
analyses of air-dried samples for DDT residues given in table 3. A much
larger amount of DDT was deposited 50 feet from the machine than at
greater distances. In considering the data presented in table 3, it
should be kept in mind that applications of insecticides to alfalfa
normally would be made 3 weeks or more before the crop is harvested.
Although growth of the crop and weathering prior to cutting would greatly
reduce the DIT content of the hay made from mature alfalfa under the
figures given in table 3, it is possible that the hay still could not be
safely fed to livestock. The residue problems involved in the application
of atomized concentrated sprays to forage crops remain to be solved. In
the meantime the use of these insecticides on forage crops that are to be
fed to livestock is not recommended.
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Table 3.--DDT residues on samples of air-dr3e /alfalfa
from areas treated by mist bloweriLt/
Formula Date treated Distani c
No.j (August) from machine DDT
Tests at Lynnhaven, Va., samples collected August 10
6 5 50 206.2
7 8 50 170.8
8 9 50 303.2
Tests at Beltsville, Md., samples collected August 28
8 15 50 476.1
10 15 50 17.1
I/ Analyses made by the Division of
2/ Analyses of untreated checks from both areas
gave negative results,
2/ May have been carried by wind from another
test conducted in the same field.
Applications to Corn
Both machines were used to apply atomized concentrated sprays to
sweet corn to control the corn earworm. The small blower was used in
3 tests to apply formula 8 on August 8 and 13; the large blower was used
to apply formula 18 on August 7 and formulas 12, 16, 17, 19, 20, 21, 22,
23, 24, and 25 on August 7 and 12. Satisfactory control of this insect
was not obtained with any of these formulas. Examination of 100 to 350
ears of sweet corn from each of the treated plots at harvesttime showed
41 to 99 percent of the ears infested, and the general average was more
than 90 percent. On August 22 an examination of 100 ears from the plot
treated with formula 21 on August 7 showed 99 infested with the corn
earworm. This treatment gave remarkably thorough and uniform coverage
of several rows of sweet corn, however, and killed a large number and
variety of insects. The orders, and number of species in each order
represented, were as follows: Orthoptera 1, Coleoptera 7, Hymenoptera 1,
Hemiptera 1, Honmoptera 1, Lepidoptera 1, and Diptera 2. Sowbugs were
Two applications of formula*6, 11, 12, 13, 14, and 15 to field
corn at Norfolk, Va., during the period August 5 to 12 to control the
fall armyworm gave unsatisfactory kill of this insect, although mortality
of the small larvae was high. This corn was very heavily infested. It
was about 24 inches high at the beginning of the treatments. Earlier and
properly timed applications may give some measure of economically practical
control of this insect.
Applications to Collards
Single applications of a dust containing 10 percent of DDT, of lead
arsenate dust, and of concentrated spray formula 11 were made to separate
plots of collards at Driver, Va., on August 8 to control the yellow-
striped armyworm. Results were inconclusive except that the spray
severely damaged the plants up to 35 rows from the machine.
Application to Woodland
On August 3 a planting of nixed pine and hardwood trees at the
Virginia Truck Experiment Station was treated with the following emulsion:
DDT 6 pounds, Velsicol AR 60 (methylated naphthalene) 7 quarts, Triton X-100
(aralkyl polyether alcohol) 10 ounces, water to make 6 gallons. An
estimated area of 6 acres was covered. A large cloth was spread under an
oak tree and many insects were down within half an hour after the insecti-
cide was applied. However, most of the species were collected the
following morning from the forest floor at various places in the woodland.
Approximately 145 species of insects belonging to 57 families and 9 species
of spiders belonging to 5 families were collected. The families and number
of species in each family represented were aq follows:
UNIVERSITY OF FLORIDA
3 1262 09239 2181
Cle ridae 1
Effect on Plants
From the tests described in this paper it seemed evident that DDT-
xylene-kerosene mixtures were much more toxic to the plants treated than
DDT-kerosene mixtures with the xylene omitted. The DDT-xylene-water
emulsions caused no injury. In descending order, collards, alfalfa, and
corn were very sensitive to formulations containing aromatic solvents,
but this injury can be avoided by a change in the mixture.