DDT Residues on Peach in Ontario1

Abstract
In an experiment on Elberta peach a DDT residue approximately 30% below the official tolerance of 7 p.p.m. was left on the fruit at harvest by the spray schedule recommended for control of the oriental fruit moth (Grapholitha molesta (Busck), Olethreutidae: Lepidoptera), namely, 2 pounds of 50% wettable powder per 100 imperial gallons on July 4 and 15 and 1 lb. on August 22, 25 days before harvest. Approximately 4.5 gallons per tree per application were applied. The tolerance was exceeded when three earlier sprays (May 27, June 5 and 17) were added to this schedule. The last spray alone (August 22) left a residue on the fruit at harvest of approximately 25% of the official tolerance permitted.

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