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The Ohio Agricultural Experiment Station (315) in 1936 reported 
that six of the most promising insecticides (including derris) for con- 
trolling three species of cabbage worms, including the imported cabbage 
worm, were tested in 1935o 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), with 
a sulfated alcohol 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) . This station 
(316) in 1937 reported that the best control of three species of cab- 
bage worms, including, th.e imported cabbage nvorm, was obtained from the 
use of paris green. Paris green sprays (2 lb. per 50 gal.) pave from 
81 to 93 percent of marketable heads; paris green dust (l lb.^12.5 
lb. flour) gave 87 percent j derris dust (l lb. of 4-percent ^errisf? lb# 
flour) gave 58 percent; and derris spray (1.5 lb. of 4-perccnt derris + 
2 oz« SS-3 to 50 gal. of water) gave 70 percent. 
According to Penick and Co. ( 326 ) in 1936, Foliafume (which contains 
derris and pyrethrum extracts) should be diluted with water 1:400 for 
use against cabbage worms. 
Shropshire and Kadow ( 569) in 1936 recommended derris and cube for 
the control of the imported cabbage worm, the cabbage looper, and larvae 
of the diamondback moth. Against cabbage worms these materials are most 
effective when applied as a dust late in the afternoon. This dust should 
contain at least 0.5 percent of rotenone and should be applied at the 
rate of 20 to 30 pounds per acre, before the worms become abundant, re- 
peating applications at intervals of 10 days to 2 weeks, or as often as 
necessary. Unlike metallic poisons, derris products are safe to use on 
crucifcrs 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. 
Walker and Anderson (467) in 1936, reporting on experiments con- 
ducted in 1932 concluded that repeated applications of derris and cube 
dusts containing from 0.5 to 0.75 percent of rotenone and from 2 to 3 
percent of total extractives, and pyrethrum dusts containing from 0.3 
to 0.5 percent of pyrethrins gave good control of cabbage worms, where- 
as dusts of weaker concentrations were loss effective. Derris and cube 
dusts having approximately the same rotenone- and total -other-extractive 
content appeared to be nbout equally effective for the control of theso 
pests, Derris dusts (0.75 percent rotenone) gave 78-oerccnt control of 
tho imported cabbage worm. -This indicates that the imported cabbage 
worm is as susceptible to derris, if not more so, than the cabbage looper 
or tho larvae of tho diamondback moth. The same authors ( 468 ) in 1937 
roportod that rcpoatod applications of derris and cube dusts containing 
from 0.5 to 0.75 percent of rotenone and from 2 to 3 percent of total 
oxtractives, at 7- to 10-day intofvals, gave good control of the imported 
cabbafee worm. 
