-87- 
F. L. Thomas ( 410 ) in 1935 recommended 1 part of derris (5 percent 
rotenone) mixed with 9 parts of finely ground conditioned sulfur for the 
control of the tomato fruitworm, Mr. Thomas ( 411 ) in 1936 reported that 
in Texas derris-sulfur dust (0.5 percent rotenone) gave good results in 
the control of the tomato fruitworm, reducing the injury from 50 to 7 per- 
cent when applied at the rate of 20 to 25 pounds per acre. 
Tischler (413) in 1935 studied the mechanism of how derris kills in- 
sects. Tests made with insects such as corn earworms led to the conclusion 
that derris inhibits oxygen utilization "by the tissues and that its detri- 
mental effects are general, rather than specific to any organ. 
Veitch (457) in 19 35 reported that in Queensland no really satisfac- 
tory spray was available for dealing with this pest, although the derris 
used for the cabbage moth and center-grub control may have had a slight 
adverse influence on corn earworm infestations. 
Walker and Anderson ( 465 ) in 1935 reported that derris and pyrethrum 
dusts had practically no effect on the corn earworm. 
White ( 460 , 481 ) in 1935 wrote that derris is ineffective against the 
corn earworm. In 1937 he ( 482 ) stated that neither derris nor pyrethrum, 
at the dilutions tested, was effective in combating the corn earworm on 
cabbage. 
App, in a typewritten report to the Division of Cereal and Forage In- 
sect Investigations, Bureau of Entomology and Plant Quarantine, United 
States Department of Agriculture, said that in 1936 he had tested a derris- 
talc dust containing 1 percent of rotenone against the corn earworm in 
Puerto Rico. Four applications of dust at 3-day intervals on December 27, 
December 30, January 2, and January 5 were necessary to keep the silks 
covered from the time the first silks appeared until they had dried up. 
This rotenone dust gave 35.51-percent control, as compared with 1.78-percent 
control from a lead arsenate-talc (8+2) dust. 
Barber, in typewritten reports to the same Division, stated that in 
1936 he made tests in southern Florida with dusts consisting of derris plus 
sulfur, dorris plus talc, and derris sprays (2 or 4 lb. per 100 gal,), plus 
sodium lauryl sulfate or sodium butyl phenyl phenol sulfonate as a wetting 
agent and bentonite (4 lb. per 100 gal.) as a sticker. All tests indicated 
poor control of the corn earworm by dorris. In 1957 he reported the results 
of laboratory tests in dusting- or spraying corn ears to prevent attack by 
earworm larvae. Powdered derris (rotenone 4 percent) and derris extract (5 
gm, rotenone per 100 cc. alcohol) were tested. Powdered derris was used in 
11 tests, diluted with talc to 1:10 and with sulfur to 1:9. It proved to 
be the least effective of the dusts studied, only 20.2 percent of the ears 
being protected, and only 33.2 percent of the larvae being destroyed. Der- 
ris was used in 13 tests at the rates of 2 or 4 pounds per 100 gallons of 
water, with stickers or a spreader alone, or in combination. This material 
was wholly ineffective in protecting ears or destroying larvae. An alco- 
holic extract of rotenone was used in 12 tests, 5 with spreaders and 7 with 
stickers. Used with spreaders, the material was ineffective, but it seemed 
to bo more effective when used with stickers, an average of 23,9 percent of 
the ears being protected, and an average of 37.5 percent of larvae being 
