■ -69- 
Several ncn&Ikaline material s y inducing finely ground, tobacco dust, fine! 
pulverized .clay, tele, tiatcmaceous earth, jn.fus.orial earth, and sulfur, 
proved satisfactory els diluents. C-ood control, was obtained with a dorris 
7 consisting of a'_ suspension of derris-rQpt powder in "water diluted tc 
contain, from. 0*0 2 to" 0.025 percent qf re tor one; ..for .example from 2 to 2,5 
pounds of derris-root powder cor.t: : n; np 4 percent of rotencne per 50 galli 
of water,. Under some conditions it .was necessary to add to the spray a nc 
alkaline spreader or, .sticker . such', as. high-grade liquid or powdered soap, 
miscible pine oil, or "one-, ci thp sulfonated oils., "White (480 ) in 1935 rec 
mended . derr is dust. (0. 5 to 1.0 percent rotenene) for the control of the ca 
V ; looppr.- Derris- spray made by adding the powder to water, ana contain 
ing 0,02 to C. 02.5'. percent of rotenone, also is' effective against cabbage t» 
to, .in 3,936, recommended derris dust containing 0.5 to 1.0 percent of rot 
none for the. control of cabbage -~ r orms on cabbage and cauliflower at a dosa 
of 15 to 20 pounds per acre. Based on the relative efficiency at the roco 
mended dosages of each of the insecticides tested, experiments indicated 
t derris end cryolite wore approximately' equal g. in effectiveness in cont 
trolling the cabbage? loopcr and that both materials are more effective tha 
ris..grsen, pyrctferuiri, or 'calcium arsenate. It was found to be especially 
important tc start the treatments on the caul ifl caver while the plants werj 
small, as it was impossible to obtain a good coverage of the insecticides i 
over the heavy foliage of nearly mature plants, .The experiments of 1934 
on collards indicate that each of the three more common species of cabbage 
worms or.-- be controlled satisfactorily with a dcrris-dust mixture contain-] 
ing 0.5 percent of rotencne. , .. 
White (482) reported that derris duet/ cbnta":r/: ; r.g' from 0.5 to 1.0 pcr4 
cent of rotencne , applied-at -the rate of 15" to 20 pounds per acre, is the 
preferred material for use against cabbage loopcr. The rotenone content 
of derris root varies, and purchases should be made on the" basis of rotcn 
one content, total extractives, and degree of fineness. For example, a 
derris-root powder containing 4 percent of rotenone should contain not 
less than Id percent' of total "6a.r6.on- tetrachloride or ether extractives. 
In general, the total 'extract should average approximately 3--1/2 times 
rotenone content. The derris-root powder should be of such degree of 
fineness that net less than 90 porccnt of it will pass through a" "200-mosh 
sieve and all the material should pass thrc ugh an 80-mosh sieve. 
I 
Tests have shown that neither paris green, -nor load arsenate, nor 
calcium arsenate will rive so effective control of cabbage loopers as will 
6 rris dusts containing 1.75 percent of rotenone applied at the rate of 12 
tb"15 pounds per aero, or pyrdthrum dusts containing 0,12 percent of pyrc- 
1 appli:.:' at the same red 'Hellebore v.»a-s found to give better 
control, than the arsonicals but was considerably inferior to the derris A 
and pyre' v ra roduots;— ifc i State b 'Department of A ;ri.pulture, Bureau o 
Entomolo - (434) in 1933. ' • • 
In l'.d v , s r 6rtcd b the United States Department of Agriculture, 
Bur niol'ogj) id Flint Quarantine (437-), 'Cory- led a discussion 
of fii I •': ro'si Lts with arsonii ] substitutes for the control of vegetable 
ina . ud The- , i | 1 , rb'portod that dbrris-sulf^ dust 
(0»5 •■■ r '■ ) sui ssj L] controlled the. cabbage loopcr. 
