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unsatisfactory as stomach poisons for third instars of the Japanese beetle 
•hen mixed "-ith soil at concentrations ranging from 250 to 2,000 pounds per acre. 
rieraing ^nd Baker ( 136 ) in 1936 -reported as follows on the use of derris 
nd its components as repellents for the Japg.nese beetle: 
A study was made of der-^is and its components under 
artificially controlled conditions to obtain further information 
on the value of these materiqls for the control of the Japanese 
beetle. Rotenonc ^as found to be 2.3 times =>s effective as 
neutrql potassium oleate as a contact insecticide, deguelin 
was equally as effective as the soap, ^nd derris wqs 0.387 times 
as effective, '^en an equal weight of castor oil ^^s added to 
the derris, the coefficient of effectiveness w^.s increased to 
0.556. ^en added to a 0.125-percent solution of coconut-oil 
soap, which alone did not kill beetles, the effectiveness of 
derris '"as increased to 1.765 times tha,t of potassium oleate. 
These data, indicate that if a small qua.ntity of soap is added 
to the derris spray in the field the effectiveness of the 
material as a contact insecticide may be greatly increased. 
Derris and its components, with the possible exception 
of rotenone, were found to be of little value as stomach-poison 
insecticides against this insect. Rotenone -"hen used at the 
rate of 4 pounds to 100 gallons "-as 53.4 percent as effective 
as acid lead arsenate used at the rate of 8 pounds to 100 gallons 
of water. Beetles fed only slightly on derris \''hen used g.t the 
rate of 2 pounds to 100 gallons. It is apparent that the repellent 
action of derris can be attributed to its rotenone and deguelin 
content. Toxicarol, tephrosin, and the der-ris resin frori Thich 
all crystalline substances had been removed had little deterrent 
effect on the insect. 
Under artificial conditions of heavy infestation, rhere the 
beetles v^ere stimulated to feed and had no choice between 
sprayed and unsprayed foliage, derris and rotenone afforded com- 
plete protection to the fruit and foliage of Yello"' Transparent 
apples, being superior to acid lead arsena.te and the lime sprays, 
which have given satisfactory results under favorable field con- 
ditions. Exposure to untraviolet light definitely reduced the 
value of rotenone as a stomach poison against the Japanese beetle. 
It was not possible to detect the change in effectiveness of 
derris because of the low toxic value of the material. The value 
of derris and rotenone as repellents "^as only slightly reduced 
by exposure to untraviolet light for 24 hours, indicating that 
the repellent effect is not destroyed so rapidly ^s the toxicity. 
Fish-oil and tannic acid did not modify the effectiveness of 
derris as a stomach- poison insecticide or ^s a repellent. Sodium 
silicate decomposed the derris and destroyed its v^lue as a repel- 
lent. 
Derris is readily crashed from foliage by water. It is be- 
lieved that this mechanical loss by the action of rain, and possibly 
dew, is one of the most imfjortant factors limiting the effectiveness 
of derris sprays for control of the Japanese beetle. Several stickers 
were tested, but none of them proved satisfactory. 
