•• 70 - 
W. H. White reported that derris and pyrethrum ifbrc approximately equal in 
effectiveness in controlling the cabbage looper, end cither was ncre effect- 
ive .than paris green, cryolite, -or .calcium. ..recnatc. In general, dusts 
gave better results than sprays. Walker and. Anderson, of the Virginia 
Truck Experiment Station, reported that a derris- dust -(0i5 percent rote- 
none) gave satisfactory control of the cabbage looper. Headlee, of Hew 
Jersey, reported that a dust containing 0.6 percent of r ie (16' parts 
derris, 25 parts sulfur, and 59 parts clay cr talc), applied at the rate 
of 15 to 18 pounds per acre without hoods, or 8 tc 10 pounds with hoods, 
■was effective . against the cabbage looper, the jfoipo r te'fl* jPJP^A -.Torn, - 
the caterpillar of the diamondback moth. The 'Surcau/ih i"0<35 i that 
laboratory experiments and largo field-plot tests to determine the re" - 
tive toxicity of pyrethrum and derris mixtures for the control of several 
, species of cabbage verms had been carried on at several laboratories, 
field-plot tests on cabbage shoved definitely' that derris-dust mixtures 
containing from 0.5 to 1,0 percent of rotencne were effective srgainst t 
common cabbage worm, less effective against the cabba -c loo id still 
less effective against the diamondbac moth. 1 c indications, 
wore that derris powder would be useful in the control of all r a species. 
In general, pyre thrum- dust mixtures were less effective th rris 
,inst all throe species. In 1936 the Bureau ( 442 ) ' reported that en cab- 
bage, derris and cryolite wore approximate 1 1 in effectiveness in con- 
trolling the cabbage looper, and both were more effective than paris green, 
pyrethrum, or calcium arsenate. Experiments in California demonstrated i 
dust mixtures of derris, cube, cr pyrethrum gave satisfactory results in the 
control of the three mere common species of cab". forms on cauliflower. 
In laboratory .tests the ground root of devil ' s-shoestrings was as effective 
against the common species of cab". . w n = e. t.o.s derris or cube contain- 
ing equal percentages cf active in ;'redicnts. 
A derris-dust mixture (20 parts derris of 5 percent rotonone c at, 
40 parts tobacco dust, and 40 parts 300-mesh due ting suifur) is v ry 
ive in controlling the cabbage looper. — Allen (ll) in 1934, 
R, E. Campbell in 1935* in a typewritten report t< the Division of "ruck 
Crop and Garden Insect Investigations of the 3ureau, gave results of field 
tests at San Fernando, Calif., in March 1934, with derris and cube 
containing 0,5 percent of rotencne on cabbage. Applications v« - et 
22 pounds per acre for derris and 30 pounds ■ re for cube by )f 
hand dusters. Derris caused a reduction of 75 percent of loopers and cuj 
a reduction of 34,4 percent. 
Crosby and Chupp (86 ) in 1934 re cor I the a dust 
containing 0,5 percent of rotencne at t r .o of 25 to 30 pounds 
for the control of lc - ; cater indue" - ] r, 
on cabbage, cr.ulifl.t-: r, brusscls sprouts, r ccol , . ' : : " r 
s on Long Island, 
Gilbert and Popenoe (l59j in 1934 recommended . 
as those produced • cr cub: r r.cntro! 
looper. I 'actory re suits ] 10 tc 1.'. 
P r acre of dust cent 1 to 2 .ne. 
dusts and extracts Footivc, 
in strength they should be used a< 
