-23- 
fl derris-clay mixture containing 1 percent of rotenone. Stoti sMcal 
calculations showed that, among 11,600 heads from a single acre, one 
U. 3. No. 1 head might be encountered that would contain 73 parts per 
million of derris (0.525 grain per pound) .— Cassil (107 ) . 
In 1941 one recommendation for the control of the imported cab- 
bage worm in New York was the use of 4 pounds of derris (4 percent of 
rotenone) to 100 gallons of water plus a suitable spreader and stick- 
er. Experiments 3howed that derris sprays of one-fourtn tnis strength 
compared favorably with the derris and pyrethrum dusts which are also 
recommended.— Pyenson and Roth (481 ) • 
Because of difference in toxicity between the yam boan and cube 
(4 percent of rotenone) in tests with the imported cabbage worm and 
coaling moth, it is probable that the toxicity of the yp.m been is not 
primarily rotenone.— Hans berry and Lee (258 ) • 
In 1941 the safest and one of the most effective methods of con- 
trol for this pest was the use of derris or cube dust mixture contain- 
ing 0.75 to 1 percent of rotenone.— U. S. Bureau of Entomology and 
Plant Quarantine ^620 ). 
Sprays or dusts containing Derris or Lonchocarpus were suggested 
for control of P. rapae in England. Dusts containing 0.1 percent of 
-otenoDe were eTfective.— Walton (655 ) . 
This species caused no damage in market gardens in Victoria where 
dusts containing derris or arsenates were employed.— Anonymous (3). 
In TTest Australia, nicotine sulfate, lead arsenete, and derris 
were recommended against this pest.— Jenkins ( 322) • 
An alcoholic extract of the seeds of Millet tla pachycarpa was ef- 
fective in China.— Chiu and coworkers (114 ) . 
Cabbage Caterpillars 
All three species of oaterpillars commonly found on cabbage in 
the United States, namely, the cabbage looper ( Trlchoplusia ni), the 
imported cabbage worm (Pieris rapae) , and the diamondbaok moth"*"'( Plutella 
maculipennis ), are either inferred or named in the following abstracts: 
In tests in Ohio with dusts applied to cabbage, the percentages 
of heads free from injury at harvest were 67 for paris green, 64 for 
lead arsenate, and 23 for derris.- Ohio Agricultural Experiment Station 
(448) . 
