Tests of new insecticides against the pepper weevil at Alhambra, California


Material Information

Tests of new insecticides against the pepper weevil at Alhambra, California
Physical Description:
6 p. : ; 27 cm.
Campbell, Roy E
United States -- Bureau of Entomology and Plant Quarantine
U.S. Dept. of Agriculture, Bureau of Entomology and Plant Quarantine
Place of Publication:
Washington, D.C
Publication Date:


Subjects / Keywords:
Pepper weevil -- Control -- California -- Alhambra   ( lcsh )
Insecticides -- Testing -- California -- Alhambra   ( lcsh )
bibliography   ( marcgt )
federal government publication   ( marcgt )
non-fiction   ( marcgt )


Includes bibliographical references (p. 3).
General Note:
Caption title.
General Note:
General Note:
"October 1944."
Statement of Responsibility:
by Roy E. Campbell.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 030286242
oclc - 779527616
System ID:

Full Text


Octbber 1944 E -627

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


By Roy E. Campbell, Division of Truck Crop and Garden Insect Investigations

During the investigations of the pepper weevil at Alhambra,
Calif., tests were made of the toxicity of many different materials,
and some of the results have been reported. The purpose of this cirmlar is to assemble and make available the information obtained on the toxicity of new material 5li in comparison with insecticides commonly used against the pepper weevil.

From a practical standpoint, cryolite was found to be the best
material to use for the control of the pepper weevil, and it has been
recommended for this purpose ( )2_. Therefore, in most cases cryolite
will be used as a standard and the effectiveness of other materials
will be compared with it. Because penner fields are continually being
reinfested with these weevils, materials which killed by contact were relatively ineffective. Only those which left a poisonous residue on
the plants for several days were satisfactory in controlling the pepper


Most of the laboratory tests were made on individual pepper
plants grown in the back yard of the laboratory. Each plant was covered
with a fiber-board cone which acted as a settling chamber and also prevented the insecticide from drifting to other plants. With the use of a precision duster (2), 1 gram of insecticide was applied to the plant
through the top of the cone. The plant was then covered with a screen cage, and 10 weevils were put into the cage. The cage was examined at
regular intervals for 4 or 5 days and the dead weevils were counted and
removed. The mortality percentage was calculated on the basis of the
dead weevils actually found, the missing ones being considered as living,
but the tests were discarded whenever more than 2 weevils were missing.

Most of the new materials were furnished by the Division of Insecticie

Underscored numbers in narenthesee refer to Literature Cited, p. I.

For testing the contact effect, the cage was put over the plant and the weevils were introduced and allowed to settle on the foliage. Then the insecticide was dusted onto the plant through he cage top, the precision duster being used.

In some special tests, cut twigs of bell pepper were used instead of plants. For each twig a glass tumbler of water was covered with a thin board 6 inches square with a hole in the center. The stem of the twig was thrust through the hole and a piece of paper fitted around the top to keep the weevils from falling into the tumbler. The twigs were dusted with an undetermined quantity of insecticide by use of an atomizer type of hand duster. The weevils were then introduced and the infested twig was covered with a lantern-globe cage.


In laboratory and field tetts made during 1931 and 1932, sodium
fluoaluminate, potassium fluoalumintae, ammonium fluoaluminate, magnesium fluoaluminate, and barium fluosilicate were effective against the pepper weevil, but these fluorine materials available at this time were somewhat unstable and caused slight leaf injury or. bud pruning, resulting in an actual reduction in yield (1). Calcium arsenate, undiluted, was almost as toxic to the pepper weevil as the fluorine materials, but a little slower in action. These tests with calcium arsenate were very favorable, and a considerable quantity was used in commercial control of the pepper weevil. The commercial use of calcium arsenate, however, was followed by damage by aphids and a decided reduction in yield (_), especially when several applications were made.

In laboratory tests in 1936, using 30 weevils for each material,
undiluted calcium arsenate gave 70 percent mortality, whereas none of the following materials gave over 40 percent mortality: Dibenzothiophene 1 and 9 percent; phenothiazine 15 percent; a mixture containing 2.7 percent of nicotine, 1.5 percent of phenothiazine, and 1.5 percent of pyri ine; a mixture containing 3 percent of phenothiazine, 3 percent of pyridine, an4
3 percent of pine oil.

In 193g and 1939 field tests were made with cuprous cyanide 20 percent and 30 percent, and with a proprietary mixture containing 0.3 percent
of pyrethrins. Infestations- were low, but cipro.1s cyanide showed some promise. Bran baits containing 4 pounds of calcium arsenate and 2 to 4 pounds of molasses per 100 pounds of bran were ineffective. A spray containing 4 pounds of tartar emetio and 10 pounds of brown sugar per 100 gallons of water was also ineffective.


As shown in tables 1 -and 2, most of the materials tested during -1940, 1941, an. 1942 were ineffective as compared with calcium arsenate and cryolite. Phenazine was toxic to the weevils but caused severe burning of the

pepper plants. Phenozathiin had to be diluted with tale before it could be used at all as a dust, and as such was relatively ineffective. Tripteygis wilfordii gave over 60 percent mortality, and it is worthy of frthoer trials, especially as the 50-percent strength averaged better than the undiluted material. Two proprietary preparations containinag pyrethrins gave high weevil mortalities when used in the laboratory as contact insecticides, but pyrethruma duste have given unsatisfactory results under field conditions. p-Aninoasobensene hydrochloride not only was ineffective, but was objectionable bea ase it gave the plants a rusty color and stained the hands and clothing of the operators yellow. p-Aminoacetanilide caused definite foliage infzt, especially to the growing tips. Phenazine, N-nitrosodiphesaylamine, styrene dibromide, and phenozathiin were all too coarse to be applied as dusts and had to be reground, which could not be done very satisfactorily with a mortar and pestle. Dimethylacridan became too moist an& ceulda not be ground at all. The sample of ground Tripterygiz wilferdi was an excellent dust, being light and easy to apply.


In 1943 two new materials, 2-chlorofluoreae and DDT, were tested, and the results as summarized in table 3, indicate that they may be more toxic than any material previously tested. DDT was consistent in giving 100 percent mortality within 214 hours after application, but very low mortalities were sometimes obtained within this period with 2-eblorofluorene. Plants treated with DDT appear to be completely protected from weevil feeding. The weevils were not able to stay an the leaves or buds for more than a few seconds at a time. The same action was observed with twigs dusted with 2-chlorofluorene, but the weevils were affected less rapidly than with the IDDT. Incidentally, the M dust adhered to the pepper leaves and buds much better than did the 2-chlorofluorene.


(1) Elmore, J. C.
1933. Some tests with fluorine compounds against the pepper
weevil. Jour. Econ. Int. 26t 1095-1105, illus.

(2)- - - - Roy E. Campbell, and C. S. Guy
1935. A method of applying insecticidal dusts quantitatively
as a basis for cage tests of insecticides. U. S. Dept. Agr., Bur.
At. and Plant Quar. Circular 3T-45, 3 pp., illus. (Processed.)

1942. The Pepper Weevil. U. S. Dept. Atr. Leaflet No. 226,
8 pp., illus.

(4) - - - and Roy Campbell
1943. Aphid increase and plant injury following the use of calcium arsenate on peppers. Jour. Econ. Znt. 36 (6): 83-56.

Table l.- Mortality of pepper weevils on plants treated
with insecticidal dusts, 19410 19)42

Materials : Weevils:Mlor:used :talit7
Number Percent
Weevils placed on dusted foliage, 19110
Calcium arsenate 200 90
Cryolite (70% sodium fluoaluminate) 2110 97
Cryolite (50% sodium fluosluminate) 270 80
1, 3Diphenyl triazine 140 77
1, 14Diphenyl semicarbazide 150 53
Phenothiazine (30%) 14o0 36
Cuprous cyanide (20%) 30 33
1,3-Diphenyltriazine and bentonite (1:1) 90 32
A proprietary mixture containing pyrethrins 2% 50 32
Diriitro-o-cyclohexyl phenol 2% and dicyclohexylamine
3*35% 100 31
Qzprous cvanide (30%) 50 .26
A proprietary material containing pyrethrum powder
15%, beta-butoxy-beta '-thiocyanodi ethyl ether 1%,
petroleum distillate 1%, and talc 83% 140 25
p-Aminob enzene hydrochloride 1140 241
flicyclohexylamine dinitro-o-cyclohexylphenate 1.7%
and heavy oil 2% 100 23
p-Aminoace tanil ide 100 22
Dicylcohexylamine dinitro-o-cyclohexylphenate 1.7% 100 20
1, 4-Dinitrosopiperazine 100 10
Dini tro-.o-cyiohexylphenol 1% 70 9
l14-Diphenyl semicarbazide and bentonite (1:1) 50 6

'Weevils placed on dusted foliage, 1911

Phthalonitrile 60 32
Phtbalonitrile and talc (1:1) 70 23
p-Aminoace tanil ide 60 12
p-Aminoacetanilide and talc (1:1) 70 17
1,41-Diphenyvl semicarbazide SC0 1)4
1,1+-Diphenyl semicarbazide and talc 70 241
p-Aminoazob enzene hydrochloride 50 33
p-Aminoazobenzene hydrochloride and talc (1:1) 70 1R
None (check) 140 10


Table 1 continued

Mateialo: 'e evils: Mor?dateialpused :tality
Number Percen~t

Weevils placed on foliage before dusting, 1911

Phthaloni trile 70 96
Phtbalonitrile aznd talc (1:1) 6o06
p-Am"inoacetanil ide 80 142
p-Aminoacetanilide and talc (1:1) 80 140
1, 4-fiphenyl semicarbazide 6o 142
1,14-Diphenyl semicarbazide and talc (1:1) 80 55
p'-Amitoazobenzene hydrochloride 70 33
p-Aminoazobenzene hydrochloride and talc (1:1) 60 33
None (check) 140 22

Weevils placed on dusted foliage,, 194+2

Phenazinei! 2/ 140 92
P1,;enazine and talc (1:1)-' 140 4.2
Cryolite (704, sodium fluoaluminate) 196 82
Cryolite (50%~ sodium fluoaluminate) 212 77
Cryolite (35%4 sodium fluoalwninate) 151 7
Tripterygium wilfo rdi i 1806
T', wilfordii and talc (1:1) 110 67
N1-Ilk tro sodiphenylam ine ~0 20
Phenoxathiln and talc (1;1) 1028
Styrene dibromide 50 24
Nodle (check) 1140 10

Caused severe burning and complete defoliation.

Caused slight burning and dropping of buds.

1111 t l Il l II I II llIIII III III I 11
-- 3 1262 09230 3972

Table 2.-Mortality of pepper weevils in tests in which 10 weevils were
placed on plants before the application of insecticides and 10
veevils 4 to 10 days later

:Tests :Mortality of :Mortality of Materials :con- :weevils :weevils placed :
:ducted :dusted son dusted :
: : :foliage :
:Number : Percent : Percent :
Calcium arsenate, undiluted : 24 : 85 : 75
Calcium arsenate and talc (1:1) : 10 : 82 : 3
Cryolite and talc (70 sodium : : :
fluoaluminate) : 20 : 86 : 64 :
Cryolite and talc (50, sodium : :
fluoaluminate) : 15 : 66 : 47 :
A proprietary material containing: : :
15 of pyrethrum powder, 11 of : : :
beta-butoxy-beta '-thiocyanodi- : : :
ethyl ethpr, 1 of petroleum : : : :
distillate and 83, talc : 14 : 87 : 24 5
A proprietary mixture containing : : 2
2 percent of pyrethrins : 15 : 88 : 25 :

None (check) : 9 : 10 : 7 :

Table 3.-Mortality of pepper weevils placed on twigs of pepper after dusting with new insecticides, 1943

Materials :Strength: Weevils :Mortality in
: : used : 24 hours :
:Percent: Number : Percent

2-ChlorofluoreneL/ : 20 : 67 : 67
: 10 : 30 : 27

DDT and pyrophyllite : 10 : 69 : 100
: 5 : 29 : 100 :
: 3 : 31 : 100 :
_* ,

Diluent not known