-54- 
Treatment 
Fruit showing — 
External insect I Codling npth 
injury 
entries 
Conspicuous 
spray russet 
Lead arsenate 1 plus 
flotation sulfur 
2 
Cryolite plus flota- 
tion sulfur 
Cryolite plus Coposil 
Derris spray 
Check— pink spray only 
Percent 
91.5 
• 65,4 
48.3 
32.0 
24.4 
Percent 
0.0 
.'8 
2.0 
.9 
3.9 
Pe re ent 
35.8 
1.3 
l/ Lead arsenate used at 3 pounds per 100 gallons. 
2/ Cryolite used at 4 pounds per 100 gallons. 
"hj Derris used at 4 pounds per 100 gallons. One extra spray in August. 
Ground root containing 4 percent rotenone combined -with skim-milk 
ponder. . 
Klinger ( 237 ) in 1936 reported that in laboratory tests en fourth in- 
stars, rotenone spray or dust gave no mortality in 8 days. 
i' . 
McGovran ( 262 ) in 1935 reported that in laboratory tests against lar- 
vae oil impregnated with 1 percent of rotenone gave between 40 and 25 per- 
cent of entries; nicotine sulfate, 2 percent in oil, gave 100-percent con- 
trol and -was the most effective material for impregnating oil. 
The Missouri agricultural Experiment Station (280) in 1936 reported 
that rotenone and a number of other chemicals proved far more toxic to 
the larvae under laboratory conditions than lead arsenate, but in the or- 
chard they did not prove effective or safe. 
Siegler and Hunger, in a typewritten report to the Division of Fruit 
Insect Investigations, of the Bureau of Entomology and Plant Quarantine 
in 1936, stated that a sample of derris containing 3.6 percent of rote- 
none (15,6 percent total extractives with carbon tetrachloride), used at 
the rate of 1 pound to 50 gallons- of water, wa- ineffective in laboratory 
tests against codling moth larvae. Tephrosia virginiana , used at a dos- 
age in which the rotenone content was the same as that of a sample of 
derris, was not quite so effective .as derris,' possibly because the per- 
centage of total extractives was only one-half that obtained from derris. 
Extracts of other plants such as T. piscatoria , Jamaica dogwood, and 
daisy flowers did not appear to have promise. 
