-52- 
F. J. D. Thomas ( 409 ), Kent, England, reported in 1935 on the control 
of 'surface-eating tortricid larvae en apples. Tests were made with derris 
dust and derris spray against Cacoecia podana Scop., to apply a protective 
dust to the fruit before an attack bega*rZ In the Latter part of June 
moths of this species and also codling moths were beaton from the trees. 
Two dusts v, r ere applied on July 17— one of derris, the other of barium 
fluosilicate. Subsequent observations and counts on both windfalls and 
crop showed very little tortrix damage to the fruit on any of the trees, 
including the undusted controls. Surface damage was mainly due to very 
young codling moth larvae and net to C. podana . * * * Derris (crude 
rctenone 3.63 percent), 2 pounds plus~"soft soap 5 pounds per 100 imperial 
gallons, reduced the damage 50 percent when applied approximately 9 v:eeks 
after petal-fall. 
Trappmann and Nitsche ( 417 ) in 1935 reported that rotenone sprays 
and dusts were not effective against the last instars of this species. 
Dosage was regulated to give a deposit of 0.18 mg. of rotenone per 500 
CO, 2 . 
The United States Department of Agriculture, Bureau of Entomology 
and Plant Quarantine ( 458 , 439), in 1935 assembled the results of codling 
moth investigations conducted during 193'. by State agencies. At Monroe, 
Oreg. , four cover sprays were applied en the apple trees. Lead arsenate 
3 pounds per 100 gallons gave 89.07 percent of clean fruit; rotenone in 
the last three covers with calcium arsenate in calyx and first cover gave 
71,76 percent of clean fruitj and rotenone plus 0.75 percent of oil Mo. 6 
in the last three covers and calcium arsenate 3 pounds per 100 gallons in 
the calyx and first cover gave 78.41 percent clean fruit. At Talent, Oreg., 
eight cover sprays were applied to apples and five or six cover sprays to 
pears. On pears derris with kaolin, 1 percent of rotenone (calyx and 
first cover lead arsenate), 5 and 10 pounds per 100 gallons, both with 
and without oil, and powdered cube root rath kaolin (rotenone 1 percent) 
at 10 pounds per 100 gallons, gave much poorer control than did lead 
arsenate. In 1934 workers in the Division of Fruit Insect Investigations 
of the Bureau, tested derris in the field at Kearneysville, W. Va, ; Saint 
Joseph, Mo. j Parma, Idaho; Hood Fiver and Talent, Oreg. ; and in the labor- 
atory at Takoma Park, Md, Derris powder was toxic to larvae under labor- 
atory conditions, Derris-kaolin applied in the field to apples, from 
which plugs were made for laboratory testing at Vincennes, Ind., was no»t 
toxic. In the field derris, cube, and pyre thrum in admixture with kaolin 
were all rated ineffective. 
Baker and Butler (20) in 1936 reported en tests made on a 20-acre 
block divided into plots of ubout 15 trees each. All applications wore 
made with a power sprayer operating at 400 pounds' pressure and carrying 
2 single-nozzle guns. Derris alone gave little or no control, but in 
combination with mineral oi] it was more effective though still far from 
satisfactory. Derris caused no foliage injury. The follow!] ble shows 
the results of field tost3 of organic substitutes for lead arsenate at 
St. Joseph, Mo., in 1934. All plats were sprayed \ I ad arsenate, 3 
pounds per 100 gallons, in tho oaly y. 
