Value of auxiliary materials in rotenone and pyrethrum insecticides for control of cabbage caterpillars

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Title:
Value of auxiliary materials in rotenone and pyrethrum insecticides for control of cabbage caterpillars
Physical Description:
24 p. : ; 27 cm.
Language:
English
Creator:
Reid, W. J ( William John ), 1902-
Cuthbert, Frank P., 1922-
United States -- Bureau of Entomology and Plant Quarantine
Publisher:
U.S. Dept. of Agriculture, Agricultural Research Administration, Bureau of Entomology and Plant Quarantine
Place of Publication:
Washington, D.C
Publication Date:

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Subjects / Keywords:
Rotenone   ( lcsh )
Pyrethrum (Insecticide)   ( lcsh )
Caterpillars -- Control   ( lcsh )
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federal government publication   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )

Notes

Bibliography:
Includes bibliographical references (p. 13).
Statement of Responsibility:
by W.J. Reid and F.P. Cuthbert.
General Note:
Caption title.
General Note:
"E-834."
General Note:
"March 1952."

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University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 030338432
oclc - 780531360
System ID:
AA00025236:00001

Full Text

March 1952


United States Department of Agriculture
Agricultural Research Administration
Bureau of Entomology and Plant Quarantine



VALUE OF AUXILIARY MATERIALS IN ROTENONE AND PYRETHRUM
INSECTICIDES FOR CONTROL OF CABBAGE CATERPILLARS

By W. J. Reid, Jr., and F. P. Cuthbert, Jr., Division
of Truck Crop and Garden Insect Investigations-


Insecticides containing rotenone or pyrethrum, or both, are widely
used on cabbage and related crops for the control of caterpillars and
certain other insects. The relatively low order of toxicity of these
materials to man makes them particularly useful for insect control
during the later stages of plant growth, when arsenical, fluorine, and
DDT insecticides cannot be safely applied because of residue hazards.
However, insecticides containing rotenone and pyrethrum are rather
expensive and have little toxicity to certain of the caterpillars (Reid
et al.4). Rotenone is effective against larvae of the diamondback moth
but does not always control the cabbage looper, whereas pyrethrum
controls the cabbage looper but is not very effective against the diamond-
back moth.
The value of auxiliary materials in rotenone and pyrethrum insecti-
cides has received considerable study in recent years. Bronson and
Dudley (2) state that the addition of a conditioning agent, nicotine
alkaloid, or a aliphatic thiocyanate increased the effectiveness of
rotenone dust against the pea aphid. In later tests (Bronson and Dudley 3)
they used a light mineral oil for this purpose. Brannon (1) reported
that "either piperonyl cyclonene or piperonyl butoxide has a synergistic
effect when used with low-strength rotenone dust mixtures against the
Mexican bean beetle." Yun-Pei Sun (6) found that the addition of a com-
mercial methyl naphthalene product increased the toxicity of rotenone-
containing insecticides to several species of insects, including the
cabbage looper and the imported cabbageworm.
Several materials that might increase the effectiveness of rotenone
and pyrethrum against cabbage caterpillars were tested on spring and fall
crops of cabbage at the South Carolina Truck Experiment Station, near
Charleston, from 1941 to 1949, inclusive. In 1941 and 1942 experiments
were also conducted to compare the effectiveness of various dust diluents
for these insecticides.

1/ In cooperation with the South Carolina Agricultural Experiment Station.


E-834





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MATERIALS USED

Most of the pyrethrum dusts were simple mixtures of ground pyrethrum
flowers with a diluent. Impregnated pyrethrum dusts were prepared by
adding a diluent to a commercial dust base impregnated with an extract of
pyrethrum flowers.
The rotenone dusts were made from cube powder unless otherwise
specified. The rotenone-impregnated dusts were received ready for use.
Dusts containing piperonyl cyclonene or piperonyl butoxide that were
not received ready-mixed were prepared from a dust base.
Unless otherwise indicated, the oil used in all dusts was a light grade
of paraffin-base refined mineral oil having a viscosity of approximately
75 seconds Saybolt (1000 F.) and an unsulfonated residue of approximately
90 percent.
The thiocyanate was a commercial product containing equal parts of
/ -thiocyamodiethyl esters of higher fatty acids and a light grade of
mineral oil.
Sprays containing n-propyl some were prepared by mixing technical
n-propyl some with an emulsifiable rotenone extract and adding water,
and dusts from rotenone or pyrethrum powder and an n-propyl some dust
base.
One part of a commercial wetting and sticking agent (consisting of
sodium sulfonates of mixed long-chain alcohol-fatty acid and diethylene
glycol abietate) was added to 4,000 parts of the sprays used in the spring
of 1949.
In the experiments to compare various diluents, a flaky Georgia talc,
dusting sulfur, a North Carolina pyrophyllite, and a South Carolina kaolin
clay were used.
Unless otherwise indicated, the percentages of constituents of the
mixtures are on a weight basis.

METHODS

In each experiment the plots were arranged in three to eight randomized
blocks. The plots consisted of either one or three rows 3 feet wide and
25 to 240 feet long, usually 50 feet. An unplanted alley about 3 feet wide
separated the ends of the plots.
Dusts were applied early in the morning, when the plants were usually
wet with dew and there was little wind. The dusters were rotary hand
machines to each of which was attached a cloth-covered hood followed by
an 8-foot cloth apron to reduce the drift and to give a more uniform
distribution. From 20 to 30 pounds were applied per acre. When the
larger plants were dusted, two trips were made per row.





-3-


Dusts not received ready for use were prepared in an electrically
operated 2-quart pebble mill, in a 50-pound sifting and ribbon-type
mixing machine, or in a 100-pound combination ribbon and hammer-mill
mixer. Each lot was run for about 30 minutes in the pebble mill or at
least 15 minutes in the largermixers. Unless otherwise specified, either
pyrophyllite or a flaky talc was the diluent of the laboratory-mixed dusts.
Liquid additives either were poured slowly and mixed with a spoon into
the diluent before being more thoroughly mixed in the pebble mill, or
were run through a paint sprayer into the diluent while it was being
agitated in the ribbon-type mixing machine.
Sprays were applied with a knapsack sprayer that maintained a fairly
constant pressure. One or three trips were made per row and from 75
to 125 gallons was applied per acre.
Counts were made of caterpillars that survived on the same number
of plants, usually 25, in each plot after each application. The plants were
taken at regular intervals throughout the plot, except the end 3 feet of
each row and the outside rows in 3-row plots. In general, the insect
count was begun about the fourth day after an application and was com-
pleted about the sixth day. All plots in a block were examined on the
same day.
In the fall of 1941 and the spring of 1942 experiments were con-
ducted to compare the effectiveness of rotenone and pyrethrum dusts
prepared with various diluents. In 1941 two applications were made,
at 18-21 and 21-22 pounds per acre. Between the third and sixteenth
days after the second application, counts were made on 300 plants
receiving each treatment (50 plants per plot in 6 replicated 3-row
50-footplots). In 1942 one application was made of each dust at 20-22
pounds per acre. Counts of surviving caterpillars were made between
the third and eleventh days on 600 plants receiving each treatment
(75 plants per plot in 8 replicated 4-row 50-foot plots). In another
experiment in the fall of 1942 the same diluents were compared in
freshly mixed and 6-months-old dusts containing 0.75 percent of
rotenone. One application was made at 24-27 pounds per acre. Two
counts were made of surviving cabbage loopers only, on the fourth or
fifth day and between the eight and eleventh days after the application.
These counts were made on 200 plants receiving each treatment (50
plants per plot in 4 replicated 3-row 50-foot plots).





-4-


TEST INSECTS

The caterpillars included in these tests were those of the diamond-
back moth (Plutella maculipennis (Curt.)), the cabbage looper (Trichoplusia
ni (Hbn.)), the imported cabbageworm (Pieris rapae (L.)), the corn ear'-
worm (Heliothis armigera (Hbn.)), the fall armyworm (Laphygma
frugiperda (A. & S.)), and several species of climbing cutworms, including
the granulated cutworm (Feltia subterranea (F.))
In the Discussion of Results the cabbage looper, the imported
cabbageworm, and the larvae of the diamondback moth are called green
caterpillars. The corn earworm, the fall armyworm, and the cut-
worms are grouped under the subfamily name "Agrotinae" and referred
to by that term or as brown caterpillars.


DISCUSSION OF RESULTS

The numbers of each of three kinds of caterpillars surviving each
treatment in the spring experiments are given in table 1, and similar
data for the fall experiments in table 2. Percentages of control
(reduction), calculated by Abbott's formula, are given where comparable
untreated plots are available.
A material was considered to be superior or inferior to another only
where differences between surviving populations were significant at odds
of 19 to 1 (5-percent level).



Impregnated Pyrethrum Dusts

In the spring of 1942 (table 1) an impregnated dust containing 0.15
percent of pyrethrins (No. 3A) was as effective against the green cater-
pillars as a simple dust containing 0.3 percent of pyrethrins (No. 2). In
the fall (table 2) two brands of impregnated dusts containing 0.15 percent
of pyrethrins (Nos. 3A and 3B) were as effective against the looper and
Agrotinae as the simple 0.3-percent dust, and were highly superior
against the loopers to a simple 0.15-percent dust (No.10). In the spring
of 1943 one of the impregnated dusts (No. 3B) tended to be more effective
against the green caterpillars than the 0.3-percent dust.
In general the impregnated dusts were more difficult to blend and
apply satisfactorily than the simple dusts.








The impregnated dusts were about as toxic as otrcr dusts of twice
their pyrethrins content. Similar results were reported by Huckett (4)
as having been obtained on Long Island, N. Y. He stated (p. 57), however,
that "Impregnated pyrethrin dusts were markedly toxic to the cabbage
looper and other cabbage worms, but for some reason not fully under-
stood they were not as consistently effective as pyrethrum dusts in field
trials."

Impregnated Rotenone Du ,ts

In the spring of 1943 a simple rotenone dust (No, 12) was su, '-rior
to impregnated dusts (Nos. 13 and 14) of one-half and one-l"-! its
strength against the looper, the imported cabbageworr., and the diamond-
back moth. In the fall of 1943 a simple 0.25-percent rotenone dust (No. 7)
was superior to an impregnated 0.1-percent rotenone dust (No. 14) a:inst
the cabbage looper and tended to be superior against the imported cabba
worm. No difference was shown between the two types of dust of the sanm
strength (Nos. 7 and 13). These tests indicated that the impregnation
process was not of appreciable value for roterone dusts.

Indalone

In the fall of 1943 the addition of Indalone tended to increase, but not
significantly, the toxicity of a 0.5-percent rotenone dust to the looper
(Nos. 18 and 20).

Methylated Naphthalene

In a pyrethrum dust. --The addition of methylated naphthalene
did not increase the effectiveness of a 0.3-percent pyrethrins dust against
any of the green caterpillars in the spring of 1947 (Nos. 2 and 38).
Adequate control of the cabbage looper was not provided by two applica-
tions of either of these dusts.

In a rotenone dust. --The addition of methylated naphthalene did not
increase the toxicity of a 0.5-percent rotenone dust to the cabbage looper
or the imported cabbageworm in the fall of 1943 (Nos. 19 and 20). Equal
parts of pyrophyllite and celite constituted the diluent of No. 19, whereas
only pyrophyllite was used in No. 20. In the spring of 1947 the addition
of methylated naphthalene to a 1-percent rotenone dust did not increase
its effectiveness against any of the green caterpillars (Nos. 43 and 28).





-6-


n-Propyl Isome

In a pyrethrum dust. --In the spring of 1949 the addition of n-propyl
some did not significantly increase the effectiveness of a 0.3-percent
pyrethrins dust (Nos. 58 and 2) against the looper or the diamondback
moth.

In rotenone dusts and sprays. --The addition of n-propyl some (Nos. 59
and 28) to a 1-percent rotenone dust increased its toxicity to the looper,
but not to the diamondback moth, in the spring of 1949. The addition of
this material to a 0.5-percent rotenone dust (Nos. 20 and 60) did not
increase its effectiveness against either caterpillar. The toxicity of an
emulsion spray containing 0.0125 percent of rotenone to each of the green
caterpillars was not increased by the addition of n-propyl some (Nos. 55
and 56).

Mineral Oil

In a pyrethrum dust. --In 1942 (fall) a dust containing 0.15 percent of
pyrethrins and lubricating oil (No. 9) was highly superior against the
cabbage looper, but not the Agrotinae, to a similar dust without the oil
(No. 10). The dust with the oil was as effective as one containing 0.3
percent of pyrethrins without oil (No. 2).

In a rotenone dust. --In a 1942 fall experiment the addition of lubri-
cating oil to a rotenone dust (Nos. 6 and 7) increased its toxicity to the
diamondback moth (not shown in table). In 1943 (fall) and 1944 (spring)
a dust containing rotenone and a light grade of mineral oil (No. 15) was
much superior against the looper to a similar dust without the oil
(No. 20). The oil was also of significant value in the control of the
imported cabbageworm in one of these tests and in the control of the
diamondback moth in the other.

In a pyrethrum-rotenone dust. --In 1945 (spring) a rotenone-pyrethrum
dust containing oil tended to be superior to one without the oil (Nos. 25 and
27), giving 18 percent better control of the looper.

Oil and Sulfur

In pyrethrum dusts. --In 1946 (spring) the addition of mineral oil and
sulfur increased the effectiveness of a 0.45-percent pyrethrins dust
(Nos. 30 and 33) against the looper and the diamondback moth, but not
against the imported cabbageworm. The oil and sulfur, however, were
not of apparent value in this dust in an earlier test of that season when
only the diamondback moth was present. Use of these additives in a





-7-


0.3-percent pyrethrins dust (Nos. 32 and 2) did not increase its
effectiveness.

In rotenone dusts. --A 0.5-percent rotenone dust containing oil and
sulfur was highly superior against the looper in the fall of 1943 and the
spring of 1944 to one without these additives (Nos. 16 and 20). The dust
with oil and sulfur was superior against the imported cabbageworm in
both experiments and highly superior against the diamondback moth in
one. These additives also increased the looper control given by a 1-
percent rotenone dust (Nos. 28 and 31) in a 1946 spring experiment.
However, they did not increase the effectiveness of a 1.5-percent rotenone
dust (Nos. 34 and 35) against any of the green caterpillars.

In pyrethrum-rotenone dusts. --In the spring of 1945 a dust containing
rotenone, pyrethrins, light mineral oil, and dusting sulfur (No. 24) was
superior against the looper, giving 27 percent better control, to a similar
dust without oil and sulfur (No. 27). The oil and sulfur did not increase the
effectiveness of this dust against the diamondback moth (the only species
present) in a 1946 early spring experiment. These additives tended to
improve the effectiveness of a dust containing 0.8 percent of rotenone plus
0.17 percent of pyrethrins (Nos. 36 and 37) against the looper in a 1946
spring experiment.

Piperonyl Butoxide

A dust containing 0.625 percent of piperonyl butoxide and only 0.05
percent of pyrethrins (No. 40) showed considerable toxicity to the green
caterpillars in a 1947 spring experiment, but was inferior to a 0.3-
percent pyrethrins dust (No. 2) against the diamondback moth. This dust
mixture (No. 40) also tended to be less effective against the looper and
the diamondback moth than one containing 0.05 percent of pyrethrins and
0.625 percent of piperonyl cyclonene (No. 39). Emulsion sprays con-
taining pyrethrins with piperonyl butoxide and with piperonyl cyclonene
(Nos. 41 and 42), applied at the same dosage of active ingredients, gave
slightly poorer results than the dusts. In a 1947 fall test a dust con-
taining 0.0625 percent of pyrethrins plus 1.25 percent of piperonyl
butoxide (No. 45) gave almost as good control of a light infestation of
the looper and Agrotinae as a 0.3-percent pyrethrins dust (No. 2), the
differences not being significant. A ready-mixed dust said to contain
0.0625 percent of pyrethrins, 1.25 percent of rotenone, and 0.625 per-
cent of piperonyl butoxide (No. 46) tended to be less effective against the
looper than a 0.3-percent pyrethrins dust.






-8-


Piperonyl Cyclonene

In pyrethrum dusts and sprays. --No significant differences in the
control of one or more of the green caterpillars were found between a
0.3-percent pyrethrins dust (No. 2) and dusts containing 0.05 to 0.1 percent
of pyrethrins plus 0.5 to 1 percent of piperonyl cyclonene (Nos. 22, 23, 39,
44, and 47), in experiments conducted during the fall of 1944 and the spring
and fall of 1947. The addition of 0.5 percent of piperonyl cyclonene increased
the effectiveness of a 0.3-percent pyrethrins dust (Nos. 50 and 2) against the
green caterpillars in the spri:-ig of 1948 and 1949, the increase being sig.iif-
icart against the diamondback moth. In the spring of 1947 an emulsion spray
was inferior against the looper and imported cabbageworm to a dust pro-
viding the same dosages of pyrethrins and piperonyl cyclor.ene (Nos. 39 and
41). The spray containing piperonyl cyclonene tended to be superior tr a
similar one with pyrethrins.and piperonyl butoxide (Nos. 41 and 42).

In rotenone dusts arid sprays. --No significant differences in control
of the green caterpillars were found in two experiments (1948 and 1949
spring seasons) between a 1 -percent rotenone dust (No. 28) and a dust
containing 0.5 percent of rotenone and 0.5 percent of piperonyl cyclonene
(No. 52). Nor were any significant differences found in another experi-
ment (1948 spring season) between a 1-percent rotenone dust and one con-
taining 0.25 percent of rotenone and 0.5 percent of piperonyl cyclonene (No.
54). The addition of 0.5 percent of piperonyl cyclonene significantly in-
creased the effectiveness of a 1-percent rotenone dust (Nos. 28 and 49)
against the looper population in a 1948 spring experiment. During this
season, however, a dust containing 0.125 percent of rotenone and 0.5
percent of piperonyl cyclonene (No. 48) was not so effective against the
looper as a 1-percent rotenone dust.
The addition of 0.05 percent of piperonyl cyclonene to an emulsion
spray containing 0.0125 percent of rotenone (Nos. 56 and 57) did not
significantly increase its effectiveness against any of the green cater-
pillars in a 1949 spring experiment.
In a single comparison in the spring of 1947, piperonyl cyclonene tended
to be more effective against the looper and diamondback moth than piperonyl
butoxide in a pyrethrum dust (Nos. 39 and 40). Piperonyl cyclonene also
tended to be more effective against the cabbage looper than n-propyl some
in a pyrethrum dust (Nos. 50 and 58) and in a rotenone dust (Nos. 52 and
60) in the spring of 1949.

In a pyrethrum-rotenone dust. --A commercial dust containing 0.05
percent of pyrethrins, 0.5 percent of rotenone, and 0.5 percent of piperonyl
cyclonene (No. 26) tended to be superior in a 1945 spring experiment against
the looper and diamondback moth to a Just of 0.15-percent pyrethrins and
0.5-percent rotenone content (No. 27).





-9-


Rotenone-Pyrethrum Mixtures

In the fall of 1942 a dust containing 0.25 percent of rotenone and
0.15 percent of pyrethrins (No. 8) was superior against the looper and
diamondback moth (not shown in table), but not against the imported
cabbageworm, to a mixture without the pyrethrum (No. 7). The mixture
containing pyrethrum tended to be more effective against the Agrotinae.
In another experiment of that season, the combination dust was not
significantly different from a 0.15-percent pyrethrins dust (No. 10) in the
control of the looper and Agrotinae. In a 1945 spring experiment a
mixture containing 0.5 percent of rotenone and 0.15 percent of pyrethrins
(No. 27) was inferior against the looper, was as effective against the
imported cabbageworm, and strongly tended to be more effective against
the diamondback moth than a 0.3-percent pyrethrins dust (No. 2). This
combination dust, however, was as toxic to each of these three species
as a 1-percent rotenone dust (No. 28). The 1-percent rotenone dust was
inferior against the looper, but superior against the diamondback moth,
to the 0.3-percent pyrethrins dust. In 1946 (spring), a combination dust
of 0.8-percent rotenone and 0.17-percent pyrethrins content (No. 36) was
superior to a 1-percent rotenone dust (No. 28) against the looper, and as
effective against the imported cabbageworm and diamondback moth.
This combination dust (No. 36) was as effective as a 0.45-percent
pyrethrins dust (No. 33) against the looper and diamondback moth and
superior against the imported cabbageworm. In the same test a 0.3-
percent pyrethrins dust (No. 2) was superior to the 1-percent rotenone
dust (No. 28) against the looper, but inferior against the imported cabbage-
worm and the diamondback moth.
The results described in the preceding paragraph gave further evidence
of earlier findings (Reid et al. 5) that at strengths ordinarily used
pyrethrum is usually more effective against the cabbage looper than
rotenone, that the reverse is true against the imported cabbageworm
and the diamondback moth, and that neither insecticide is very toxic to
the Agrotinae. In later studies a 1.5-percent rotenone dust (No. 34), a
1-percent rotenone dust at higher dosages than used for the 1.5 percent,
and combination rotenone-pyrethrum mixtures (such as No. 27) usually
gave satisfactory control of the green caterpillars, especially when a
light mineral oil and sulfur were used.
Huckett (3, p. 56) reported that dusts of 0.5- to 1-percent rotenone
content were less effective than dusts of 0.5- to 0.6-percent pyrethrins
content against severe cabbage looper attacks.

Sulfur

In a pyrethrum dust. --In 1942 (fall) a pyrethrum dust containing
sulfur (No. 11) was slightly but not significantly more effective against the
looper, but not against the Agrotinae, than a dust without the sulfur (No. 10).





-10-


In a rotenone dust. --The addition of dusting sulfur to a rotenone dust
containing light mineral oil did net increase its effectiveness against the
looper and the imported cabbageworm in the fall of 1943 (Nos. 15 and 16).
During the spring of the following year, the mixture containing sulfur
(No. 16) was more effective against the looper and the diamondback moth.
When these dusts were stored for 3 1/2 years and used in the spring of
1947 (Nos. 15A and 16A), no difference was found in the degree of control
of any of the green caterpillars.

In a pyrethrum-rotenone dust. --The addition of sulfur increased the
kill of the looper and imported cabbageworm given in a 1945 spring test
by a rotenone-pyrethrins-oil dust (Nos. 24 and 25). (See discussion of
oil and sulfur used together, page 5.)

Thiocyanate

In pyrethrum dusts. --In a 1942 fall experiment a dust containing 0.15
percent of pyrethrins and 2 percent of an organic thiocyanate (No. 1) was
superior against the cabbage looper, but not the Agrotinae, to a straight
0.15-percent pyrethrins dust (No. 10). This pyrethrum-thiocyanate dust
was as effective as a 0.3-percent pyrethrins dust (No. 2) against each of
the green caterpillars in 1942 spring and fall experiments.

In rotenone dusts. --In two experiments (1943 fall and 1944 spring)
the effectiveness of a 0.5-percent rotenone dust against the looper was
increased significantly by the addition of 2 percent of an thiocyanate
(Nos. 17 and 20). In the 1944 experiment the dust containing thiocyanate
gave 28 percent better control of the loopers. The thiocyanate appeared
to be of value in the control of the imported cabbageworm in both experi-
menits and the diamondback moth in the spring of 1944.

Comparisons of Diluents

In the experiments comparing diluents for rotenone and pyrethrum
dusts, those containing pyrophyllite, sulfur, and talc proved more
generally effective against the cabbage looper and the diamondback
moth than comparable dusts in which kaolin was the diluent. The
differences were most pronounced in the pyrethrum dusts and in the
control of the cabbage looper. Differences in the control of the looper
and diamondback moth provided by the dusts containing talc, sulfur,
and pyrophyllite were not significant. No significant differences
between any of the mixtures in the control of the imported cabbageworm
and the Agrotinae were apparent. The imported cabbageworm was
easiest to control and the Agrotinae were most difficult with the insecti-
cides used.





- 11 -


From table 3 it is evident that the dusts containing kaolin were
inferior to those containing the other diluents against the looper and the
diamondback moth.
Roienone dusts proved superior to pyrethrum dusts in the control of the
diamondback moth and imported cabbageworm, but inferior against the
looper, when the data were grouped without respect to the diluent. The
pyrethrum dusts were more effective against the Agrotinae, but neither
dust gave adequate control of these species.
In the 1942 fall experiment (table 4) a rotenone dust diluted with
kaolin was inferior against the looper to rotenone dusts containing sulfur,
pyrophyllite, or talc.
In freshly mixed dusts pyrophyllite was the best diluent, proving
superior to kaolin. In 6-moths-old dusts sulfur was the best. The
freshly mixed dust containing pyrophyllite proved superior to the corre-
sponding 6-moths-old mixture against the looper. The age did not
significantly affect the other dusts.
In tests on Long Island Huckett (3, pp. 54 and 57) found that pyrethrum
dusts containing clay had superior dusting qualities to those containing
other diluents, with the possible exception of pyrophyllite. However,
the clay dust did not always give a higher degree of insect control. In
fact, pyrethrum dusts containing considerable proportions of clay (more
than half the amount of pyrethrum powder present) invariably were less
effective than most others under field conditions. This was particularly
true of impregnated pyrethrum dusts. Talc, pyrophyllite, clay, gypsum,
and diatomaceous earth were the diluents compared in these experiments.

SUMMARY

Field-plot tests were made at Charleston, S.C., from 1942 through
1949, of several materials that might increase the effectiveness of
pyrethrum and rotenone insecticides against cabbage caterpillars. These
insecticides were also tested in impregnated dusts. In addition, com-
parisons were made of talc, sulfur, pyrophyllite, and kaolin as diluents
in pyrethrum and rotenone dusts.
The insecticides were applied with hand dusters or sprayers, usually
at dosages of 20 to 30 pounds of dust or about 100 gallons of spray per
acre-application. The results were based on numbers of caterpillars,
by species, surviving on an average of 25 plants per plot.
ihe species included were the cabbage looper (Trichoplusia
ni (Hbn.)), the imported cabbageworm (Pieris rapae (L.)), the
diamondback moth (Plutella maculipennis (Curt.)), the corn earworm
(Heliothis armigera (Hbn.)), the fall armyworm (Laphygma frugiperda
(A. & S.)), and several species of climbing cutworms, including the
granulated cutworm (Feltia subterranea (F.)).





-12-


In general, insecticides containing pyrethrum proved more effec-
tive against the cabbage looper than those containing rotenone. The
reverse was true of the imported cabbageworm and the diamondback moth.
Neither of these insecticides gave satisfactory control of the Agrotinae.
The auxiliary materials usually were of most value in pyrethrum insecti-
cides in the control of the imported cabbageworm and diamondback moth,
and in rotenone insecticides in the control of the cabbage looper.
Impregnated pyrethrum dusts usually proved more effective against
the caterpillars than ordinary dust mixtures of the same pyrethrins
content, but they were more difficult to blend and apply. An impregnated
rotenone dust was no more effective against the caterpillars than an
ordinary dust of the same rotenone content.
The auxiliary materials that proved of significant value were mineral
oil, mileral oil and sulfur, piperonyl cyclonene, and an organic thiocyanate.
Very few comparisons were made between these additives in any one
experiment. Rotenone dusts containing 2 percent of oil proved superior
to those containing 2 percent of a commercial thiocyanate said to contain
50 percent of oil.
A combination of 2 percent of mineral oil and 10 percent of dusting
sulfur gave the highest increases in caterpillar control. Piperonyl
cyclone apparently increased the effectiveness of low-strength pyrethrum
or rotenone dusts, but even the mixtures did not always give adequate
caterpillar control. The looper control afforded by a 1-percent rotenone
dust was significantly increased by the addition of 0.5 percent of piperonyl
cyclonene, but this additive did not sufficiently improve a 0.3-percent
pyrethrins dust to control a heavy cabbage looper infestation.
Indcalone, methylated naphthalene, n-propyl some, piperonyl butoxidcle,
and sulfur (used alone) did not prove of significant value when added in
pyrethrum and rotenone insecticides, but they usually tended to increase
their toxicity to one or more species of caterpillars.
Rotenone and pyrethrum dusts with flaky talc, sulfur, or pyrophyllite
as the diluent were generally more effective against the cabbage looper and
the larvae of the diamondback moth than the same dusts diluted-with
kaolin. A rotenone dust containing pyrophyllite was more effective
against the looper when freshly mixed than when it was 6 months old, but
the age did not significantly affect rotenone dusts prepared with sulfur,
talc, or kaolin.





-13-


LITERATURE CITED

(1) Brannon, Loyd W.
1947. Piperonyl cyclonene and piperonyl butoxide as synergists
with rotenone. Jour. Econ. Ent. 40: 933-934.

(2) Bronson, T. E., and Dudley, J. E.
1938. Conditioning agents for increasing the effectiveness of
rotenone-bearing dusts against the pea aphid. Jour.
Econ. Ent. 31: 414-419.

(3) Dudley, J. E., and Bronson, T. E.
1944. Strength of rotenone dust mixtures and rate of application
in pea aphid control. Jour. Econ. Ent. 37: 643-646.

(4) Huckett, Hugh C.
1940. Non-arsenical dusts for cauliflower and cabbage worm
control on Long Island. N.Y. (Geneva) Agr. Expt. Sta.
Bul. 695, 58 pp.

(5) Reid, W.J., Jr., Smith, Chas. E., Reed, L. B., and Thomas, W. A.
1941. Field studies of insecticides used to control cabbage cater-
pillars in the South. U.S. Dept. Agr. Tech. Bul. 782,
35 pp., illus.

(6) Sun, Yun Pei
1946. A preliminary study of the influence of Velsicol AR-60
upon the insecticidal effectiveness of dusts containing
rotenone or DDT. N.Y. (Cornell) Agr. Ent. 1
(Mimeographed).







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Table 3. --Surviving caterpillars and
with rotenone and pyrethrum dusts


pupae per 106 plants on cabbage treated
containing various diluents-1


Rotenone 0.75%


Talc
Sulfur
Pyrophyllite
Kaolin


Pyrethrins 0.2%


Talc
Sulfur
Pyroph
Kaolin


57
62
yllite 53
2/ 78
LSD-- 12.


188
171
190
217
8 43.


26
25
25
28
3 ns


Rotenone 0.75%
Pyrethrins 0.2%


All
All


LSD -


Talc
Sulfur
Pyrophyllite
Kaolin
LSD -


1_/ Data for
spring of 1942;
ment.


cabbage looper represent experiments in the
those for other caterpillars represent only


fall of 1941 and
the 1942 experi-


2/ See footnote 1, table 1.


108
108
124
144


Both


77
63
6.4

63
70
64
82
9.0


19
26
3.2


121
192
21.7

148
140
157
181
30.6






-24-


Table 4. --Surviving caterpillars and pupae of the cabbage looper
on cabbage treated with freshly mixed and 6-months-old
rotenone dusts containing various diluents. Fall of 1942.


Diluent Age of dust First count Second count


Talc

Pyrophyllite

Sulfur

Kaolin


Sulfur
Talc
Pyrophyllite
Kaolin


All


Old
Fresh
Old
Fresh
Old
Fresh
Old
Fresh /
LSD-=- -

Old and fresh
do.
do.
do.
LSD --

Fresh
Old
LSD - -


1/ See footnote 1, table 1.


UNIVERSITY OF FLORIDA

3 1262 09239 6323 1
3 1262 09239 6323


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30
36
26
25
28
37
33
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32
32
35
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14
16
7
18
12
18
20
9.3

15
14
11
19
6.6