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Rotenona and copper-rotenone were called good for cabbage worms 
in viotory gardens in Indiana in 1943 •— Reed (496) • 
The only satisfactory substitute for rotenone inseotioides for 
use on cabbage after the heads begin to form is pyrethrum.— Reid (497) . 
As arsenioals cannot be safely used on cabbages after the head 
begins to forn, dusts of derris and pyrethrum were tested in South 
Carolina in 1939 and found effective against larvae of some of the 
three species, but derris was more effective against the population as 
a whole and could be used at greater dilutions.— Reid and Bare (498) • 
Of the materials tested derris dust gave the most uniform re- 
sults in 1941* From field experiments it was concluded that a derris 
dust containing 1 percent of rotenone should be most effective against 
the cabbage looper and diamondback moth, and a 0*6 peroent dust should 
be sufficient where the imported cabbage worm predominates. In 1942 
investigations were conducted on the number and schedule of applica- 
tions of derris-China clay dust containing 0.5 percent of rotenone 
to proteot cabbage from damage by these three species* The following 
treatments resulted in a considerable Increase in marketable cabbage* 
three applications of this dust between the time the first heads be- 
gin to form and the beginning of harvest; or three applications of 
paris green and lime before formation of the first heads, followed by 
two of derris dust during the heading period.— Reid and coworkers (499 , 
600) . 
In Louisiana in 1938 three applications of a derris dust (0.6 
percent of rotenone) failed to give satisfactory protection.— Smith 
and Brubaker (547) . 
In field tests in Connecticut in 1945 against a light infesta- 
tion of the imported cabbage worm and diamondback moth, and a severe 
infestation of the cabbage looper, 1 part of derris suitably diluted 
with pyrophyllite was as effeotive as 2.6 to 6 parts of derris diluted 
with clay. If the control obtained by 1 percent of rotenone and clay 
is accepted as the desirable standard, not more than 0.4 percent of 
rotenone with pyrophyllite produced the same degree of control. Not 
more than 0.3 percent of rotenone with pyrophyllite would be required 
to equal the control following use of 0.75 percent of rotenone with 
clay.— Turner (602) • 
In order to conserve rotenone, pyrethrum can be substituted for 
it. It is better to apply an insecticide at reduced concentration 
to the entire crop rather than the full concentration to only part of 
it.— Turner and Horsfall (606) • 
