1, 4-Diphenyl semicarbazide as an insecticide

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Material Information

Title:
1, 4-Diphenyl semicarbazide as an insecticide
Physical Description:
11 p. : 27 cm.
Language:
English
Creator:
Gahan, J. B
Swingle, M. C
Phillips, Arthur M., 1903-
United States -- Bureau of Entomology and Plant Quarantine
Publisher:
U.S. Department of Agriculture, Bureau of Entomology and Plant Quarantine
Place of Publication:
Washington, D.C
Publication Date:

Subjects

Subjects / Keywords:
Biphenyl compounds   ( lcsh )
Insecticides   ( lcsh )
Genre:
bibliography   ( marcgt )
federal government publication   ( marcgt )
non-fiction   ( marcgt )

Notes

Bibliography:
Includes bibliographical references (p. 11).
General Note:
Caption title.
General Note:
"E-549."
General Note:
"September 1941."
Statement of Responsibility:
by J.B. Gahan, M.C. Swingle, and A.M. Phillips.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 030285260
oclc - 779487036
System ID:
AA00023062:00001

Full Text





September 1941


1,4-DIPHENYL SEMICARBAZIDE AS AN INSECTICIDE

By J. B. Gahan, M. C. Swingle, and A. M. Phillips,
Division of Control Investigations



In the search for insecticidal materials among organic compounds,
which has been the subject of toxicological studies at Sanford, Fla., 1,4-
diphenyl semicarbazide showed promising results on many of the insects
against which it was tested. A patent application on the compound as an
insecticide has been filed by A. F. Freeman, of the Division of Insecticide
Investigations. The application was based, in part, on certain of the
results presented in this paper.

1,4-Diphenyl semicarbazide is a white or cream-colored crystalline
solid, insoluble in water, and moderately soluble in alcohol and acetone.
It can be ground to a fine powder for dusting or readily suspended in water
for use as a spray. At present the compound is not manufactured at a price
permitting its use as a commercial insecticide, but if sufficient demand
arises to justify manufacturing the material in large quantities it may be
possible to reduce the cost greatly. The samples of derris and lead arsenate
used as standards of comparison were finely ground commercial products.
The derris sample contained 4.5 percent of rotenone.

Insects Tested

Since many organic compounds are specific in their toxicity, it was
considered that a few tests on a large number of species of insects would
furnish more useful information than many replicated tests on a few species.
This compound was tested on 14 species, representing the orders Lepidoptera,
Coleoptera, Isoptera, and Orthoptera. The majority of the tests were made
on leaf-feeding lepidopterous larvae, since the highly susceptible species
were members of this order. The insects used and the foliage fed to each
were as follows:

Insect Foliage

American cockroach (Periplaneta americana (L.)) None
Bean leaf roller (Urbanus proteus (L.)) Bean
Cabbage looper (Autographa brassicae (Riley)) LiBo$R4 1 ds

STATh PL- A BOAI4


E-549





-2-


Insect (Continued) Foliage

Colorado potato beetle (Letinotarsa decemlineata (Say)) Epl ant
Cross-striped cabbage worm (Erestis rimosalis (Guen.)) Collards
Diamondback moth (Plutella maculipennis (Curt.)) Do.
Greenhouse leaf tier (Phlytaenia rubigalis (Guen.) Do.
Hawaiian beet webworm (Hymenia fa-cialis (Cram.)) Swiss chard
Imported cabbage worm (Pieris rapae L.) Collards
Melonworm (Diaphania hyalinatI (L.)) Pumpkin
Rice weevil (Sitophilus or, z1 (L.)) Wheat (seeds)
Southern armyworm (Prodjenia eridania (Cram.)) Collards
Southern beet webworm (Pachyzncla bipunctalis (F.)) Swiss chard
Termites (Reticulitermes sp.) None

In the preliminary Petri-dish tests beet leaves were used with the
Hawaiian beet webworm and the southern beet webworm and squash foliage with
the melonworm. However, the plants listed above were used in al1 other
tests.

Details of the technique employed have been described in a previous
paper by the authors (2) and are only briefly reviewed here.

Preliminary Petri-Dish Tests

Preliminary tests were made in Petri dishes to determine whether the
material was toxic to insects and to select the species that were suscepti-
ble. Excised leaf sections dusted rather heavily with undiluted 1,4-diphenyl
semicarbazide were fed to nearly full grown larvae of 10 species of leaf-
feeding insects. For each test the dust was applied to two leaf sections
by exposing the top and bottom surfaces to a falling column of dust in a
settling chamber. At the same time an aluminum plate was exposed and the
weight of the dust deposit on the leaf calculated by subtracting the original
weight of the plate from its weight after exposure. As the purpose of these
tests was to show merely the species of insects that were susceptible to the
compound, no attempt was made to control the amount of chemical that was
applied to the foliage, nor were comparisons made with commonly used insec-
ticides. Each dusted leaf section was placed in a Petri dish with 12 to 15
larvae. Since two dishes were used per test the average number of insects
per test was 25 to 30. The dishes were held at room temperature for 48 to
72 hours before the amount of feeding was estimated and mortality counts
were made.

The data in table 1 show 1,4-dlphenyl semicarbazide to be highly
toxic to larvae of the greenhouse leaf tier, the Hawaiian beet webworm, the
southern armyworm, and the southern beet webworm. Little mortality of the
Colorado potato beetle and diamondback moth larvae was recorded, but the
compound was very repellent to these insects and greatly restricted their
feeding. Extending the duration of the test might have resulted in greater
mortality. Although in the test against the melonworm there was a poor kill
with moderate feeding, subsequent tests, to be discussed later, showed much
greater mortality of this insect. In several tests the cabbage looper, the
cross-striped cabbage worm, and the imnorted cabbage worm fed heavily with no
apparent deleterious results.





3-

Table l.--Preliminary tests on the toxicity of foliage dusted
with 1,4-diphenyl semicarbazide in closed Petri dishes

Estimated


Cabbage looper


Colorado potato beetle

Cross-striped cabbage worn


Diamondback moth

Greenhouse leaf tier


Hawaiian beet webworm

Imported cabbage worm




Melonworm

Southern armyworm


Southern beet webworm


Insec


feeding on
second day


t


Deposit

Micrograms
per sq. cm.

125
140

140

125
140

170

170
170

170

155
230
340
355

115

140
170
125
170

* Percent kill in 3


LMRARY
,STApyh pLANT W)AMW


Much
do.

Slight

Much
do.

Slight

Slight
do.

Slight

Much
do.
do.
do.

Moderate

Slight
do.

Much
Moderate

days.


Kill in
2 days
Percent


0
0

3

0
0*

30

60
100

100*

0
6
12
0

16

83
83

76*
100






-4-


Fumigation Tests in Petri Dishes

To check the possibility that the mortalities recorded in table 1
had been caused by a fumigating action of the material, a second type of
Petri-dish test was conducted with the greenhouse leaf tier, the Hawaiian
beet webworm, the southern armyworm, and the southern beet webworm. Approx-
imately 0.5 gram of chemical was confined in the top of several Petri dishes
between two pieces of filter paper to prevent the insects from coming into
direct contact with it. Larvae were placed in each dish and allowed to
feed on untreated leaf sections at room temperature for 48 hours. All the
insects fed heavily and suffered no apparent injury during a 2-day period;
it was therefore assumed that the chemical had not killed by fumigation in
the previous Petri-dish tests.

Comparison of Compound with Standard Insecticides
in Petri-Dish Tests

Fourth instars of the southern armyworm and fifth instars of the
southern beet webworm were used in a series of Petri-dish tests to compare
the toxicity of equivalent deposits of 1,4-diphenyl semicarbazide and
lead arsenate on excised foliage. Fifth instars of the Hawaiian beet web-
worm and the melonworm were used in another series in which derris instead
of lead arsenate was used for comparison, Deposits of approximately 50,
100, 150, and 200 micrograms per square centimeter were used in these com-
parisons, but the exact amount of' chemical applied could not be determined
until the aluminum plate inad been weighed.

The results in table 2 are based on a series of 3 tests using 25 to
30 insects per test. Tney show that each of the dusts gave considerable
control of all insects, the control being more or less proportionate to the
amount of chemical used, In no case was lead arsenate or derris markedly
superior to 1,4-diphenyl semicarbazide, and against two insects the standard
was less toxic. Against the Hawaiian beet webworm and the southern army-
worm there was no great difference between 1,4-diphenyl semicarbazide and
similar weights of the standard. However, the compound was somewhat more
toxic to the melonworm than was derris, being more toxic at 52 micrograms
than derris at 200 micrograms per square centimeter. The southern beet
;ebworm was the most resistant of the four species, but again 1,4-diphenyl
semicarbazide caused higher mortality in 3 days than did the standard
insecticide.

Comparison of Compound with Standard Insecticides as Sprays
on Potted Plants

Since 1,4-diphenyl semicarbazide was as toxic as derris or lead
arsenate in the Petri-dish tests, and had no fumigating action, it was
next employed as a spray on potted plants against fifth instars of the
Hawaiian beet webworm, the melonworm, the southern armyworm, the southern
beet webworm, and the greenhouse leaf tier.







5-


Table 2.--Toxicity of 1,4-diphenyl semicarbazide as compared with a standard insecticide
when dusted on foliage and fed to nearly full grown larvae of several species confined in
Petri dishes


4-Dijhen~I semicarbazide
Deposit Feeding on Kill in
third day 3 days
Micrograms Percent
per sq. cm.


Standard insecticide
Deposit Feeding on Kiil in


thi rd day


Micrograms
per sq. cm.


3 days
Percent


Derris (4.5 percent rotenone)


Hawaiian beet
webworm


Melonworm


52
i0o
148
197

52
100
150
197


Slight
do.
do.
do.

Slight
do.
do.
do.


78
87
93
95

100
i03
99
100


55
100
150
197

55
100
152
200


Slight
do.
do.
do.

Slight
do.
do.
do.


Lead arsenate


Southern
armyworm


Southern beet
webworm


52
100
147
195

53
100
148
197


Slight
do.
do.
do.


87
99
97
i00


Moderate
do.
do.
do.


52
101
155
195

52
101
155
197


Slight
do.
do.
do.


Moderate
Slight
do.
do.


insect


90
97
99
99





-6-


One diffiuity encountered in the testing of organic chemicals as
insecticides has been the preparation of good spray suspensions. Most of
the che:i1als that have been used are niot readily dispersed when mixed with
water and either sink to the bottom of the container or float on the surface
v7 the water, With 1,4-diphenyl semicarbazide it was necessary to use a
wetting or dispersing agent. Saponin was finally selected as a suitable
agent and was used at a concentration of 0.12 percent. The saponin, 1,4-
diphenyl semicarbazide, and enough water to form a thin paste were ground
together in a mortar, and when the combination was thoroughly mixed it was
gradually diluted to the proper concentration with water. A cream-colored
suspension resulted, which sprayed satisfactorily. Similar sprays were
made with derris and lead arsenate for comparison with the 1,4-diphenyl
semicarbazide.

Treatments were applied to potted plants at concentrations of 1, 2, 4,
and 8 pounds per 100 gallons of water, the application being made with a
compressed-air gun of the type commonly used in paint-spray outfits. To
prevent a heavy loss of chemical from run-off, spraying was discontinued
as soon as the droplets on the leaves began to coalesce. Two plants sub-
jected to the same spray were included in each test. After the sprays had
dried, approximately 15 insects were placed on each plant and a cylindrical
screen cage was superimposed over it, Observations were made every 2 days
for insect mortality and an estimate of the amount of feeding.

The results of this experiment are shown in table 5. They furnish
additional evidence that 1.4-diphenyl semicarbazide is as -oxic as derris
or lead arsenate to the five species of insects used. In fact, the mortality
of the Hawaiian beet webworm, the melonworm, and the southern beet webworm
was higher at every concentration than at the same concentration of the stand-
ard. A 4-100 spray appears to be as effective as an 8-10O spray, but in most
cases tnere was a definite decrease in toxicity when the concentration was
reduced Lo 2-iOO. Feeding was slight in most tests except those with the
southern beet webworm.

Pnytotoxicity Tests

To ascertain whether 1.4-diphenyl semicarbazide can be used with
safety on tender foliage, heavy sprays were applied at concentrations of
S-00 and 4-100 to young bean, collard, escarole, lettuce, pumpkin, spinach,
swiss chard, and tomato plants growing in direct sunlight in a garden.
These tests were made in the spring of the year when the weather was warm
but not hot. 3ix plants of each species were used at both concentrations.
All plants were covered during rainy weather and at night to prevent the
chemical from being washed off the leaves.

No injurious effects were noticed on any of the plants after one
application of the spray, but aLter a second application, made 1 week later,
some chlorosis and browning along the edges of a few leaves was observed on
the tomato plants. This injury occurred on foliage sprayed at the 4-100
as well as the 8-100 concentration. No injury to the other species was
aoted -within a f-day period following the second application of spray.







-7-


Table 3.--Toxicity of 1,4-diphenyl semicarbazide as compared with a standard insecticide when applied
as sprays to potted plants infested with nearly full grown larvae of several insects


Concentration
of
insecticide
Pounds per
100 gallons


Hawaiian beet
webworm


_i,4Di henylsemicarbazde
Tests Feeding on ___ Kill after-
sixth day 2 days 4 days 6 days
Number Percent Percent Percent


3 Slight
do.
do.
do.

2 Moderate
Slight
do.
do.


Melonworm


Standard insecticide
Feeding on Kill after-
sixth day 2 days 4 days 6 days
Percent Percent Percent
Derris


Moderate
Slight
do.
do.


64
95
98
100


87
100
i00
100


Slight
do.
do.
do.


Lead arsenate


Southern
armyworm


Southern beet
webworm



Greenhouse leaf
tier


3 Slight
do.
4 do.
do.

6 Moderate
do.
do.
Slight

1 Slight


14
27
59
54

100


54
85
99
100

47
46
88
86

100


Moderate
Slight
do.
do.


Slight
do.
do.
do.

Slight


insect


65
91
100
100


21
29
69
69

100


10
15
43
53

100





-8-


Field-Laboratory Tests

In the potted-plant tests it had been observed that on leaves sprayed
with an effective concentration of 1,4-diphenyl semicarbazide most of the
feeding took place the first night, although some of the insects did not
die until the sixth day. It was therefore assumed that these tests showed
the toxicity of tne compound only during the first 24 hours. Another type
of test was desirable to check the possibility of a change in the toxicity
of the residue after it had been exposed for several days to such weather
factors as sunlight and air currents. This information was obtained by
cutting leaf samples from sprayed plants in the garden at 2-day intervals
and feeding them to fifth instars of the melonwoim and southern armyworm in
Petri dishes. Parallel tests were made with lead arsenate and derris.
These tests were also made in the spring of the year. No information was
obtained on the effect of rainfall, as the plants were protected during
snowers and at night.

The spray mixtures were prepared by grinding the samples to a paste
in a mortar with an equal weight of bentonite and a small amount of water
and then diluting to a concentration of 8 pounds per 100 gallons. Sodium
lauryl sulfate was also used in the sprays applied to collards to make them
spread on the waxy surface of the leaves, but no spreading agent was required
on the pumpkin leaves. Applications were made with a knapsack sprayer to
seven plants until the large droplets on the leaves began to coalesce.
As soon as the spray was dry and on the second, fourth, sixth, eighth, and
tenth days thereafter, six leaves were picked at random and placed indi-
vidually in Petri dishes with five insects. On the second, third, fourth,
and fifth days after sampling the dishes were examined for dead insects and
feeding.

The results of these tests, which are given in table 4, show clearly
that 1,4-diphetyl semicarbazide did not lose its toxicity wnen exposed to
sunlight and air currents for 10 days. As in the previous tests, the
melonworm was still the more susceptible insect, a better kill being obtained
in 3 days than with the southern armyworm in 4 days. The compound was
superior to the derris standard in every test with the melonworm, and in some
cases it was more effective against the southern armyworm than was lead
arsenate. Feeding by the southern armyworm was confined to several small
holes in each leaf section, but somewhat heavier feeding was recorded in
the melonworm tests with both compounds. In no case was feeding heavy
enough to cause severe damage.

Field Tests against Bean Leaf Rollers

In Florida the bean leaf roller is a serious pest of beans auring
the fall of the year. A practical experiment was therefore made on a row
of bean plants heavily infested with first, second, and third instars of
this insect. A spray using 6 pounds of 1,4-diphenyl semicarbazide and
6 pounds of bentonite to 100 ai]1ons of water was applied with a 3-gallon
knapsack sprayer until the droplets on the leaves began to coalesce. When
the row was examined 4 days later, no living bean leaf roller larvae were
found.












- 9 -


Table 4.--Results of tests with leaf samples taken at 2-day intervals from plants sprayed in the
garden with 1,4-diphenyl semicarbazide and with the standard insecticide and fed to nearly full grown larvae
of the southern armyworm and the melonworm in Petri dishes


Time
between
Insect spraying
and
sampling
Days


4-Dipenyl semicarbazide
Feeding Kill after -
after 2 days 3 days 4 days


4 days
Percent


Percent Percent


Standard insecticide
Feeding _Kill after -
after 2 days 3 days 4 days
4 days
Percent Percent Percent
Derris


Check_(uns praye
Feeding Kill after-


after 2 days
4 days


3 days 4 days


Percent Percent Percent


Melonworm


Moderate
do.
do.
do.
do.
do.


86
53
86
76
100
90


93
80
93
100
100
96


Moderate
do.
do.
do.
do.
do.


Lead arsenate


Southern 0
armyworm 2
4
6
8
10


Slight
do.
do.
do.
do.
do.


Heavy
do.
do.
do.
do.
do.


Slight
do.
do.
do.
do.
do.


Heavy
do.
do.
do.
do.
do.






- 10 -


Tests against Cockroaches, Termites, and the Rice Weevil

1,4-Diphenyl semicarbazide was also tested against the American
cockroach, termites, and the rice weevil. Only preliminary tests were made
with each species, as the results were not sufficiently promising to en-
courage further work.

The tests on cockroaches were made by dusting a 6-inch sheet of filter
paper and placing 10 to 15 adult insects on it in the bottom of a 7-inch
battery jar. The inside of the jar was greased with baseline to prevent
the roaches from escaping. No mortality occurred in 3 days when a deposit
of 310 micrograms per square centimeter was used. In the same period of
time a sodium fluoride deposit killed 70 percent of the roaches.

A technique devised by Hockenyos (1) was used in the tests against
termites. Tests were made at concentrations of 1-1,000, 1-3,000, and
1-5,000, but the mortality was never greater than 19 percent in 3 days.
A phenothiazine standard killed all the insects in 2 days at the 1-1,000
concentration.

In the tests against the rice weevil a sample of wheat was coated
with the chemical (1 part by weight of chemical to 1,000 parts of wheat)
by shaking the two together in an Erlenmeyer flask, and then placed in a
Petri dish with 25 weevils. A mortality of 28 percent resulted in 4 days.
However, in similar tests with derris and lead arsenate standards at the
same concentration only 20 percent of the weevils were killed.

Summary

Several types of toxicity tests were made with 1,4-diphenyl semi-
carbazide. When dusted on foliage and placed in Petri dishes, the chemical
was highly toxic to nearly full grown larvae of the greenhouse leaf tier,
the Hawaiian beet webworm, the melonworm, the southern armyworm, and the
southern beet webworm arid repellent to larvae of the Colorado potato beetle
and the diamondback moth, but ineffective against the cabbage looper, the
cross-striped cabbage worm, and the imported cabbage worm. It was about
as toxic as the standard insecticide to the Hawaiian beet webworm and the
southern armyworm, but more toxic than the standard to the melonworm and
the southern beet webworm.

In spray tests on potted plants the compound was as toxic as the
two standard insecticides to the five species that were found highly suscep-
tible in the Petri-dish tests, A 4-100 spray was as effective as an 8-100,
but in general there was a decrease in toxicity when the concentration was
reduced to 2-100. The deposit showed no loss in toxicity after exposure
to weathering for 10 days. Spray applications, at concentrations of 8-100
and 4-100, to young bean, collard, escarole, lettuce, pumpkin, spinach,
swiss chard, and tomato plants growing in a garden, caused some chlorosis
and browning on the tomato plants after the second application, but no
injury that was noticeable on the other species.






- 11 -


In preliminary tests the compound was not sufficiently toxic to the
American cockroach, a species of termite, and the rice weevil to encourage
additional testing.

Literature Cited

(1) Hockenyos, G. L.
1939. Laboratory evaluation of soil poisons used in termite con-
trol. Jour. Econ. Ent. 32: 147-149.


(2) Swingle, M. C., Phillips, A. M., and Gahan, J. B.
1941. Laboratory testing of natural and synthetic organic sub-
stances as insecticides. Jour. Econ. Ent. 34: 95-99, illus.




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