- 74. - 
and pyre thrum dusts containing from 0.3 to 0.5 percent of pjretl rins gave 
good control of cabbage worms, whereas dust of weaker concentrations 
were less effective. .Derris and cube- dusts having approximately the same 
rotenone and total-ether-extractive content appeared to be about equally 
effective. Derris dusts (0.75 percent rotenone) gave 68 percent control of 
the cabbage looper, indicating that the imported cabbage worm is as sus- 
ceptible to derris, if not more so, than the cabbage looper or the larva 
of the diamondback moth, ftalksr and flnderson ( 4-68 ) in 1937 reported that 
repeated applications of derris and cube dusts c ntaining from 0.5 to 0.75 
percent of rotenone and from 2 to 3 p rcent of total extractives at 7- 
to 10-day intervals g°ve good control of the cabbage looper. 
Walker ( 4-63 ) in 1937 reported that cube dusts (0.75 percent rotenone) 
and sprays (3 pounds p r 100 gallons), both with and without Ultrawet, 
were used to control the cabbage looper. In most cases the adc ition of 
Ultrawet did not result in increased protection of the plants. The sprays 
and dusts without Ultrawet usually provide*-! adequate control. 
Headlee ( 186 ) in 1935 reported good control of cabbage loop- rs in 
New Jersoy with a dust c insisting of 16 parts of ground derris (5 percent 
rotenone and 18 percent total extractives) , 25 parts of sulfur, and the 
remainder clay or t lc. '''hen applied without hoods from 1 L " to 18 pounds 
per ac 8 ware necessary; and with hoods, p rom 8 to 10 pounds. 
Howard in a typewritten rep rt to the Division, in 1935 stated that 
derris powder mixed with t^-lc, infusoria" 1 earth, or tobacco dust so as to 
c ntain fr r m 0.5 to 0.75 percent of rotenone and used at intervals of 7 
to, 10 days at dosages of 25 to 30 pounds per acre per application was 
fairly effective against the cabbage looper. 
Howard and Davidson ( 195 ) in 1935 advised that derris sprays or dusts 
gave best control of cabbage worms in Ohio. For the control of the looper 
it was necessary to use derris or cube dusts containing 0.4- to 0.5 percent 
of rotenone, or to use derris or cube-root sprays containing 0.015 to 0.02 
percent of rotenone. Applications were made every 10 to 14- days after 
large numbers of worms appeared. There was no significant difference in 
the degree of control obtained ..from the use of derris-root or cube-root 
dusts or sprays, provided the rotenone c ntents were practically equivalent. 
The addition of spreaders or stickers to derris-root suspensions in water 
applied as sprays seemed slightly to increase the control obtained. \ T ery 
little difference in the degree of control resulted from the use of a 
number of diluents for derris or cube dusts. . 
Howard, Mason, and Davidson ( 197 ) in 1935 reported that derris dust 
was fairly effective against t) 1 per in Ohio. 
The Ohio Agricultural Eaq tit St.tion ( 314. ) in 1935 re] r1 I tests 
x>f 23 insecticides against cabbage worms, including the cal I r, 
the imported cabbage worm, and the diamondback moth. The control obtained 
by any toxic agent was greater ''-hen the mate! L« 1 w< li i in dust, form 
than when ap lied as a spray. On the basis of marketable ""boa It- bed, 
5 materials, differing little in efficiency from one another, were defin- 
itely superior to the other 18. These r , listed in ord ' Lr effect- 
iveness, were as follows: 
