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Walker and Anderson ( 470 ) in 1940 reported that several tests had 
been conducted with dusts containing calcium arsenate and hydrated lime 
and v/ith rotenone-bearing dusts at Norfolk, Va., in the preceding 5 years. 
In these tests, even though the spinach leaves appeared to be well covered 
with the dusts, none of the materials gave satisfactory control. Occas- 
ionally the worms disappeared without seriously damaging the spinach, which 
probably accounts for many of the reports that the calcium arsenate dusts 
gave good control of this pest. 
Kellula undalis (F. ), the cabbage webworm 
Watanabe (474) in 1927 recommended spraying the young growth of cru- 
ciferous vegetables with derris to combat this species in Japan. 
At the 1934 meeting of the American Association of Economic Entomolo- 
gists, as reported by the United States Department of Agriculture, Bureau 
of Entomology and Plant Quarantine (437), Cory led a discussion of field 
results with arsenical substitutes for the control of vegetable insects. 
White reported derris to be effective against the cabbage webwom. In 
general, dusts gave better results than sprays. The Bureau ( 455 ) in 1934 
stated that the preferred dust for the control of the wobworm on cabbage is 
derris or other rotenone dust and that the preferred spray is combined 
pyrethrum-derris extract, 
Veitch ( 457 ) in 1935, reporting on tests made in Queensland, stated 
that derris was effective against the larva, which tunnels in the stem of 
cabbage. 
White (481) in 1935 summarized the results obtained by the Bureau of 
Entomology and Plant Quarantine at Chadbourn, A r . C, Charleston, S. C., 
Baton Rouge, La., and Columbus, Ohio, with nonarsenical insecticides for 
the control of the cabbage webworm. Derris gave the best results. Appli- 
cations were begun when the worms first appeared on the plants. White 
( 482 ) in 1937 reported that results of experiments in 1936 indicated that 
the cabbage webworm can be controlled by applications of dust containing 
0.5 percent of rotenone, provided applications are made during the ^arly 
stages in the growth of both insects and plants, and the plants are covered 
thoroughly with the dust. 
Walker and Anderson (467) in 1936 reported tests made in 1932. A 
derris extract containing 5 gm. of rotenone per 100 cc. of solution, usrd 
at the rate of 1 part by volume to 200 and to 400 parts of water cor. 
ing 0.5 percent of Red A soap, gave only 11 and 9 percent control, respec- 
tively. Dusts containing 50 percent by "weight of calcium arsenate, 25 per- 
cent of cryolite, 25 percent of Dutox, 5 percent of . rid 0,4 
percent of rotenone gave from 10 to 21 percent control. 
C. E. Smith ( 373 ) in 1937 reported tests made at 3a ton Rou, , I . In 
field experiments involving several species i rms, principally 
Autographa brassicae (Riley), Hellu la undalis ( F. ), and Fieri s rapao (L. ), 
a dust mixture of peat moss containing '?. percent of nio otine was distinctly 
inferior in insecticidal efficiency to dorris-uust mixtures contail .5 
and 1,0 percent of rotenone, and also to an undiluted tri-c^lcium areonato. 
