BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 67 
To determine whether there was translocation of parathion within 
the treated plant, clusters of tomatoes were bagged after pollination 
or when fruits were small. Such bagging eliminated direct contami- 
nation by contact with the parathion applied, so that any parathion 
detected by analysis would have to be by translocation. These fruits 
contained no significant amount of parathion when harvested. Un- 
bagged fruits on the small plants contained a maximum of 2.36 p. p. m. 
Parathion was not translocated from treated f oilage to bagged tomato 
fruits nor from treated soil to fruits. 
Another phase of this experiment showed that biweekly aerosol 
applications resulted in a parathion residue on tomato fruits of 2.51 
p. p. m. the day after treatment and 0.14 p. p. m. after 14 days. A 
similar experiment on cucumber showed a residue on the fruits of 0.62 
p. p. m. On lettuce the residues ranged from 34 to 97.8 p. p. m. im- 
mediately after treatment and fell to 0.7 p. p. m in 17 days in two tests 
and to 2.0 p. p. m. in 20 days in a third. Sulfotepp residues were 
somewhat lower than parathion and decreased at about the same rate. 
Spray Deposits by Different Applicators Analyzed 
In cooperation with the Washington State Department of Agricul- 
ture, analyses were made at Yakima of deposits of methoxychlor and 
lead arsenate applied by several different types of applicators for con- 
trol of the cherry fruit fly. Hand spray guns and speed sprayers gave 
deposits in about the same range. Lead arsenate applied as dust 
either from ground dusters or helicopters gave much lower deposits 
than sprays. No correlation was found between the quantity of 
insecticide deposited and the degree of control of the cherry fruit fly. 
Persistence of Soil Insecticides Observed 
Soil samples from plots at the Irrigation Experiment Station, Pros- 
ser, Wash., were also analyzed at Yakima. These were taken in the 
spring of 1951, a year after treatment with DDT or chlordane. A 
high percentage of the DDT was still present in the soil but the 
greater part of the chlordane had disappeared. 
DDT Soil Content Increased in Sprayed Orchards 
The DDT content of soil in four apple orchards near Yakima has 
been analyzed for 4 years. The amount of DDT that accumulates 
in the soil from spray deposits has increased each year. 
Insecticidal Residues Analyzed 
Insecticidal residue on peaches that had received spray schedules 
using parathion, DDT, or EPN alone or in mixtures for oriental fruit 
moth control were determined at Moorestown, N. J. Analyses were 
made immediately after spraying and at weekly intervals until har- 
vest. The harvest residues of parathion and EPN were only a fraction 
of a part per million. The DDT residues at harvest were about 7 
p. p. m. 
Also at Moorestown, analyses were made of methoxychlor and DDT 
residues on corn leaves sprayed by airplane with commercial emul- 
sions at the rate of 1.5 pounds to the acre in 5 gallons of emulsion. 
