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TVhite ( 482 ) in 1936 and again in 1937, recommended derris dust con- 
taining 0.5 to 1.0 percent of rotenone for the control of cabbage worms on 
cabbage and cauliflower at a dosage of 15 to 20 pounds per acre. The ex- 
periments indicated that derris and calcium arsenate are approximately 
equal in effectiveness in controlling the larvae of the dianondback moth, 
while pyrethrum, cryolite, and paris green are relatively less effective. 
It v/as found to be especially important to start the treatments early in 
the development of the cauliflower, since it was not possible to obtain a 
good coverage over the heavy foliage of nearly mature plants. The experi- 
ments on collards in 1934 indicated that each of the three more common 
species of cabbage worms may be controlled satisfactorily with a derris- 
dust mixture containing 0.5 percent of rotenone-. 
Van der Vecht (454) of Buitenzorg, Java, in 1936 reported that tests 
of derris against this species yielded the same results as against 
Crocidolomia binotalis . 
The New Jersey Agricultural Experiment Station ( 295 ) in 1937 reported 
that derris dusts gave satisfactory results on cabbage worms, including 
this species. 
The New South Wales Entomological Branch (296) in 1936 described the 
use of derris powder for controlling the larvae. For cabbage and cauli- 
flower, lead arsenate was mixed with an equal part of kaolin, while pure 
derris powder was mixed with 8 parts of kaolin or talc. On no account should 
lime be mixed with derris, as it reduces its efficiency. 
The Ohio Agricultural Experiment Station ( 315 ) in 1936 reported that 
six of the most promising insecticides (including derris) were tested in 
1935 against cabbage worms, including this species. The insecticides were 
used in various strengths and with different diluents, stickers, and 
spreaders. The highest percentage (97 percent) of marketable heads was 
produced on plots sprayed weekly with paris green (2 lb. to 50 gal. of 
water) in which a sulfated alcohol was used as a wetting agent. Averages 
of 90 to 93 percent of marketable heads were produced on plots dusted at 
weekly intervals with derris powder and flour (0.5 percent rotenone). 
The same station ( 316 ) in 1937 reported that the most successful control 
of cabbage worms, including this species, was obtained from the use of 
paris green. Paris green sprays (2 lb. per 50 gal.) gave from 81 to 93 
percent of marketable heads; paris green dust (l lb. + 12.5 lb. flour) 
gave 87 percent; derris dust (l lb. of 4-percent derris + 7 lb. flour) 
gave 58 percent; and derris spray (1.5 lb. of 4— percent derris + 2 oz. SS-3 
to 50 gal. water) gave 70 percent of marketable heads. 
Shropshire and Kadow ( 369 ) in 1936 recommended derris and cube for the 
control of this species. Against cabbage worms these materials are most 
effective when applied as a dust containing at least 0.5 percent of rote- 
none late in the afternoon at the rate of 20 to 30 pounds per acre. Appli- 
cations should be made before the worms become abundant, being repeated at 
intervals of 10 days to 2 weeks, or as often as necessary to prevent fur- 
ther injury. Unlike metallic poisons, derris products are safe to use on 
crucifrars up to the time of cutting. Derris sprays, while not commonly 
recommended, can be used for the control of cabbage worms. They should be 
used according to the manufacturer's directions. 
