- 110 - 
Fleming ».nf'. Baker ( 135 ) in I93U rrportcd thp off ectiv^npss of stonach- 
poison insocticides on the Japanese boetlo, Dihyclrorotenonr, rotenone, ?.nd 
drrris (U pprcent of rotr-none) wore spra.j'ed of dusted on the foliage of potted 
s-nartweed, FolvgemuB^pGnns^>^lvrnica'n . and after standing SU hours the plants 
were placed in glaps cages vrith Jat)ancse 'bcotleg. The cages were kept at 
85° to 90° F., with a relative, hujniditr of 90 to 95 percent, under artificial 
yellow light of an intensity of ?5 candlenieters. Lead arsenate at g pounds 
per 100 g--^ lions was taken as the stand'=rd of co'np^r'ison (coefficient of 
effectiveness l.OOO), the mortality heing figured at the end of Ug hours. 
Results obtained vrith dihydrorotenone rotenone and derri<5 were as follows; 
: Concentration ! 
■: of naterial '.Coefficient of 
Material : Ih./lOO gal. :effectiveneg5 
Pure "Dowdercd dihydrorotenone 
plus fish oil (U:l) 
Do. ' 
Do. 
Do.- 
2 
6 
dust 
Pure powdered rotenone 
Derris (U percent rotenone) 
Do. 
Do. 
Do. 
dust 
20 
Uo 
60 
SO 
O.lUg 
.•^gu 
.U21 
.981 
■ .7:^2 
■^ .517 
■ .6go 
l.Ulo 
1.275 
When dihydrorotf-none vras dissolx'od in acetone at the r^tc of 2 
gn. to 100 cc. and padded to water, it was found that a concentrption 
eouivfilent to 6 pounds to 100 gallons of water was the mp,ximura that could 
bn kei^t in suspension, and' it vras less than half as effccti-"-e n,s the 
standr.rd. The beetles were largely' repelled from folia.ge sprayed with 
derris powder mixed with vrat^-^r in conc^-ntrations ranging f row: 20 to gO 
pounds to 100 gallons. From the coefficients of effect i-"-ens<^.- it appears 
that about 50 pounds of derris powder should be eouivalent to g pounds of 
lead arsenate as a stoinach poison a.gainst the Japanese beetle, 
Lnter in IS^^theco authors, in a tyr)ewritten report to the Chi^f 
of the Eurepu of Entomolog?-- and Plant Q,uarantine, stated that under artificial 
conditions of hea'"'y infestation complete protection was afforded to the fruit 
and folirge of Yellovr Transparent apples by the application, of sprays con- 
taini-g derris or rotencne. Lime spra."-.s did not protect the fruit from 
attack, although thf feeding on foliage vras sonevrhet redviced. Beetles fed 
to only a limited extrnt on fruit fprayc d with acid lead arsenate. 
Hellebore and pyrothrum ha-e no value as stomach poisons or aa re- 
pellents against the Jap-nes beetle. Derris is a vreak stomach poison but 
a definit' repellent. The repellent action of derris appears to be due 
to the rotenone a.nd the deguelin. The toxicarol, tephrosin, and. resinous 
residue appear to be of no value as repellents. Degi.i.elin wa^^ foundu to bo 
equal to neutral potassiun-oleate soap as a contact insecticide, a.nd roten- 
one WPS 2,3 times as effective, -'-'orris vras only about one-third as effect- 
ive when used alone; but, vrhen O.I25 percent of potasslun-coconut-oil soa^p, 
an amount below that cffecti"e against the beetle, vras added, derris became 
1.765 ti"ion more effective than the potassium-olcate soap in killing beetles. 
