-165- 
The Alabama Polytechnic Institute (10) in 1935 reported that derris 
dust was effective in controlling cabbage worms. 
Elmore, Campbell, and Guy ( ill ) in 1935 described a precision duster 
for use in cage tests of insecticides. One gnu of dust (derris diluted 
with talc) deposited an average of 1.3 mg. of dust per square inch, with. a 
range of 1.2 to 1.33 mg. in four' different applications. Tests showed a 
consistent increase in mortality of cabbage worms with an increase in the 
percentage of rotenone. 
Ginsburg and Granett ( 166 ) in 1935 discussed arsenical substitutes. 
Derris mixtures were cited as examples of internal poisons that have 
proved a valuable adjunct in the control of beetles and caterpillars in- 
festing vegetables, ornamental plants, and house insects. 
Huckett and Hervey ( 204 ) and the United States Department of Agricul- 
ture, Bureau of Entomology and Plant Quarantine ( 437 ), in lgSS^eported 
results of tests with derris and cube in western New York and/Long Island 
in 1934. The derris contained 5.3 percent of rotenone and 21 percent of 
total extractives. The cube contained 5.1 percent of rotenone and 20 per- 
cent of total extractives. Dust mixtures containing either powdered derris 
or cube root, prepared from roots having nearly the same average content of 
rotenone and total extractives compared favorably in effectiveness with one 
another when used against cabbage worms. The differences in results ob- 
tained with mixtures containing 0.5 to 1 percent of rotenone were small and 
variable, indicating that the weaker strength is satisfactory for practical 
purposes and, for reasons of economy, would be preferable to the 1-percent 
mixture. All wero superior in effectiveness to dusts containing 0.33 per- 
cent of rotenone. Talc, clay, finely ground gypsum, and sulfur-clay were 
satisfactory diluents or carriers. Spray mixtures containing derris powder 
were slightly more effective than those containing cube powder. The sprays 
were not quite so effective as derris or cube in dust mixtures. 
Two applications of a proprietary dust containing 0.75 percent of ro- 
tenone at the rate of 10 pounds per acre gave commercial control of cabbage 
worms in Aroostook County. — Maine Agricultural Experiment Station ( 266 ) 
in 1935. 
Polvosol was advertised in England, according to Miles and Miles ( 278 ) 
in 1935, for the control of caterpillars. A highly concentrated liquid- 
derris preparation, Polvosol kills at 1:400 and is particularly suitable 
for oedema-susceptible plants. Sprays containing derris are valuable al- 
ternatives to nicotine sprays and have a much wider range of use because 
they are effective against caterpillars. Generally used at the rate of 2 
pounds of finely ground derris root to 100 gallons of water, with 6 to 10 
pounds of soft soap or l/2 to 1 pound of a suitable wetting and spreading 
agent. 
R. J. Prentiss & Company, Inc., in advertising literature in 1935 
stated that for the evaluation of insecticidal dusts less emphasis should 
be placed on rotenone content and more on total ether extractives. Dusts 
were prepared from derris containing 5 percent of rotenone and 18 percent 
of total ether extractives, and also from another lot of derris testing 1 
percent of rotenone and 18 percent of extractives. Dusts wore made from 
t] ■ containing in each/lb pounds of powdered derris and 85 pounds of clay. 
