BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 23 
control, largely because of their greater residual effectiveness. After 
a hot, dry period in New York, a leaf scorch developed on Bosc and 
to a lesser extent on Bartlett pear trees sprayed with parathion. 
Insect pests of stone fruits 
In orchard tests against the plum curculio in Georgia, parathion 
and benzene hexachloride were superior to toxaphene or lead arsenate 
in preventing premature dropping of fruit and in holding the infesta- 
tion in drops to a low level. Benzene hexachloride, parathion, and 
toxaphene, as used in regular schedules, caused no injury to peaches 
and did not affect the flavor of the fresh fruit. Both hexaethyl tetra- 
phosphate and technical tetraethyl pyrophosphate, 1-800, injured 
peach foliage in Georgia, and the latter also injured fruit. Residue 
analyses indicate that about half the parathion deposited on peaches 
by spraying in Georgia is lost within 11 days after application and 
nearly all is lost within 4 weeks after spraying is discontinued. 
In Indiana an infestation of the peach-tree borer was reduced to a 
very low level with as little as 4 pounds of a 6-percent gamma benzene 
hexachloride wettable powder per 100 gallons applied to the base and 
the trunk of peach trees early in October. A 10-pound dosage was 
also highly effective. This insecticide, as used, was more effective 
than either 2 or 5 pounds of a 25 -percent parathion wettable powder 
per 100 gallons. 
In Maryland a preliminary field test was made to determine the 
effect of the relatively pure isomers of benzene hexachloride. alone and 
in combination, on the odor and flavor of fresh, canned, and frozen 
peaches. No off-odors that could be attributed to any of these isomers 
were obtained, but the delta isomer showed the greatest tendency to 
cause off-flavor, followed by the beta isomer. 
Good control of the oriental fruit moth with DDT was obtained in 
tests in New York, New Jersey, and Ohio. However, schedules that 
will give good control of moderate to heavy infestations are likely 
to leave excessive residues at harvest. The most effective schedule 
tried in New York included two applications of 2 pounds of 50-percent 
DDT per 100 gallons against the second brood and one application of 
1 pound against the third brood. In Ohio best control was obtained 
with two applications of 2 pounds of 50-percent DDT per 100 gallons, 
the first application 8 weeks and the second 3 or 4 weeks before harvest. 
These schedules in New York and Ohio left residues in excess of 
7 parts per million. In New Jersey, under conditions of heavy in- 
festation, 2 pounds of 50-percent DDT per 100 gallons reduced injury 
to peaches by 17 to 100 percent, depending on the number and time 
of the applications. One or two applications of such a spray 3 weeks 
or more before harvest reduced fruit injury by about 50 to 60 percent. 
and harvest residues were below 7 parts per million. When more 
than two applications were made, however, with the last about 21 days 
before harvest, or applications were closer than 21 days to harvest, 
control was better but harvest residues were generally above 7 parts 
per million. 
Parathion was extremely promising for oriental fruit moth control 
in New York, New Jersey, and Ohio. In New York ryania and 
