Residues of Diazinon in Carrots After Treatment Against Cyclodiene-Resistant Carrot Rust Fly1

Diazinon granules were applied to carrots at the recommended rate of 2 lb toxicant per acre in the seed furrow, supplemented with drenches of 10 oz toxicant at weekly intervals to protect the crop from Psila rosae (F.). Additional plots with similar furrow treatments were supplemented with 2 and 3 times the rate for drenches. Analyses to determine residues showed that the recommended rate did not result in residues above tolerance, but that double the rate resulted in residues exceeding the tolerance of 0.75 ppm 28 days after the final application. At 3 times the recommended rate residues were 1 ppm 70 days after the final application.