-. 51 - 
Aphids on cabbage 
Fhite (304) in 1935 and again ( 306 ) in 1936 stated that tests have 
indicated that derris dusts may aid in the control of certain aphids that 
infest cabbage and related crops, 
DeBussy et al. (31) in 1936 stated that aphids can be readily con- 
trolled by spraying with a suspension of derris having a rotenone concen- 
tration of 1:10,000 or by spraying with a pure-rotenore suspension 
containing rotenone at a concentration of 1:5,000, During 1935 deBussy 
and associates used derris dusting powders (0,5 percent rotenone plus 1,2 
percent ether extract) against several varieties of leaf lice, including gray 
aphids on cabbage seed. There was no kill of these insects. From this it 
is concluded that in only a few cases can satisfactory results against 
aphids be expected when derris powder is used as a dust. Spraying v/ith 
derris extracts 1.-; to be favored. 
Derris dusts effective against cabbage worms do not give satisfactory 
control of plant lice,— Colorado Agricultural Experiment Station (50) in 
1936. 
The New South Wales Entomological Branch -(209) in 1936 reported 
that, where derris dust is applied throughout the season at 7- to 10-day 
intervals for the control of Plutella maculipennis (Curt.), it will also 
check green aphid infestation but does not control the slaty-gray aphids. 
Merino and Otanes ( 197 ) in 1938 recommended a derris-soap spray 
for the control of aphids on cabbage. Either dried or fresh derris roots 
may be used, 
Aphids on cauliflower 
Infestations of aphids in the cauliflower seedbed during July were 
effectively controlled by dusts containing 0.5 and 0,33 percent of rotenone. 
The applications were made late in the evening under calm conditions, in 
anticipation of high relative humidity during the night. — New York 
Agricultural Experiment Station (213) in 1937, 
Aphids on Ceylon ironwood 
Miller ( 201 ) in 1935 tried aphids or Ceylon ironwood ( Me su a ferrea L. ) 
as test insects in determining the irs-ecticidal value of various species 
of derris, but they proved too susceptible and difficult to handle; 100- 
percent mortality was obtained each time, not only with the insecticide 
but also with the control fluid. 
Aphids on cherry 
Earfoot (12) in 1935 stated that the cherry and, pear growers of the 
Bay district of California used several tons of cube dust for the control 
of aphids and ether insects. 
