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Gunderson (173) in 1938 recommended derris with or without sulfur fo 
the control of cabbage worms, including the looper. Flour, sulfur, pearl 
dust, gypsum, and other carriers are given as diluents for preparing derriaj 
dust, A 1-percent-rotenone dust is usually strong enough for all needs. j 
cabbage loopers if applied when the worms were very small. Nothing gave ■• 
exceptionally good results against full-grown cabbage loopers. "White re-| 
marked that derris and cube" dusts control the cabbage looper to some ex- 
tent if applied while the worms are small. 
C. E. Smith (372, 373) in 1937 reported tests made at Baton Rouge, La, 
In field experimenTs"invoTving several species of cabbage worms, including 
the looper, a dust mixture of peat moss containing 2 percent of nicotine \ 
was distinctly inferior to derris-dust mixtures containing 0.5 and 1.0 per- 
cent of rotencne, as well as to an undiluted tricalcium arsenate. There 
v/as practically no difference between the efficiency of the derris dust coi 
taining 0.5 percent of rotenone and that of calcium arsenate, but a derris- 
dust mixture containing 1.0 percent of rotenone was distinctly superior to 
the other three materials tested, when applied at intervals of 2 weeks. 
Field tests at Baton Rouge showed that derris-dust mixtures containing 1 A 
or 0.5 percent of rotenone were superior to nicotine-peat dust in control- 
ling the more common species of cabbage worms, including the cabbage loopei 
Parks and Pierstorff ( 324 ) in 1938 recommended a rotenone spray or 
dust to control the cabbage looper on cabbage and spinach. 
Roark (357) in 1938 reviewed the comparative action of derris and cute 
of equal rotenone content on many insects.' Reference was made to a type 
written report by R. E. Campbell to the Division of Truck Crop and GardeiT 
Insect Investigations in 1934 in which he said that derris caused a reduc -■ 
tion of 75 percent and cube a reduction of 34.4 percent in numbers of cat ■. 
bage loopers (0.5 percent rotenone in each dust), and to talker and Ande 
(465) who in 1935 reported that, based on rotenone content, a cube dust 
not seem to give quite so satisfactory control of cabbage loopers as did a 
derris dust. 
Agicide DC-4 (rotenone 0*6 percent) §t the rate of 4 pounds per 100 
gallons of \mtor (0; 003, percent ■rotenone- in spray) killed from 50 to 100 
percent within 96 hours."— Agicide Laboratories ("8'). In 1939, 
Crosby et al . (87) in 1939 wrote that rotenone dust* is not entirely 
effective against large cabbage loopers, but that the so can be controlled 
with a pyrethrum dust containing from 0.5 to 0.6 percent of pyrethrins or 
an impregnated dust containing from 0.3 to 0.5 percent of pyrethrins. 
Since the looper, as well as green cabbage worms and diamondback moth lar-i 
vac, is a problem under Long Island conditions, growers may generally choc 
pyrethrum dust as the most effective material for controlling all three 
posts, A grower who wishes to economize on the cost of his insecticides I 
use a rotenone dust early in the season and transfer to a pyrethrum dust J 
later (about August 15 on Long Island) or when loopers aro present. Eac 
duct should bo applied at the rato of 25 to 50 pounds per acre per appli 
tion. 
