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Parlcs and Pierstorff ( 524 ) in 1938 recommended derris spray to control 
leaf roller on rose and strawberry, 
Roark ( 557 ) in 1938 reviewed the comparative action of derris and cube 
of equal rctenone content on cabbage worms. He referred to Howard and 
Davidson ( 195 ), who found derris and cube dusts and sprays equally effec- 
tive, and to Huckett and Kervey ( 204 ), who reported the dusts to be equally 
effective but spray mixtures containing derris slightly more effective than 
those containing cube, 
Derris products may be used very effectively against smooth-bodied 
caterpillars. — Warwick ( 471 ) in 1938. 
The Yifisconsin Agricultural Experiment Station ( 488 ) in 1938 reported 
that trials carried on in the Racine-Kenosha, truck-crop area since 1933 
showed that rotenone dust (0,75 percent rotenone) is one of the most effec- 
tive insecticides for cabbage worms, being more effective than sprays of 
the same material. 
According to Faloon ( 116 ) in 1939 the addition of 15 parts of litho- 
pone zinc sulfide pigment to a mixture of 15 parts of derris or cube pow- 
der (5 percent rotenone) and 70 parts of kaolin increased the time during 
which the dust was toxic to cabbage worms. 
Haude in 1939, in advertising literature published by John Powell and 
Co., New York, N, Y, , stated that the United States Department of Agricul- ■ 
ture recommended a dust containing 0,75 percent of rotenone for use against 
leaf-eating caterpillars on "greens" such as spinach, lettuce, and turnip, 
but should be used prior to harvest to avoid excess arsenical residues, 
Rotenone dusts are effective in controlling numerous leaf-feeding cater- 
pillars but their use has not been extensive because of their cost. 
An anonymous (7) writer in 1940 said it is believed that derris and 
pyrethrum compounds should give the same results on cauliflower, broccoli, 
kale, or collards, as when used on cabbage, provided the affected parts of 
the plant can be well covered. Preliminary experiments in California have 
shown that derris, or cube, or pyrethrum-dust mixtures, at the same dilu- 
tions as have been mentioned for cabbage (4 percent derris 1 part, 3 parts 
diluent) gave as satisfactory results in the control of the three more com- -5| 
mon species of cabbage caterpillars on cauliflower as they did nn cabbage. 
It was found. to be especially important to start the treatments early, while 
the plants were small, since it was not possible to obtain a good coverage 
over the heavy foliage of nearly mature plants. Good results were also 
obtained against cabbage caterpillars on cauliflower with sprays of derris- ' 
root powder containing from 0,02 to 0,025 percent of rotenone (viz, 2 to 
2-1/2 pounds of derris-root powdor containing 4 percent of rotenone per 50 
gallons of water). ' 
