Dissipation of quinalphos on mango (Mangifera indica L.) fruit

A supervised trial was undertaken at Tamil Nadu Agricultural University Orchard, Coimbatore, India, to test the dissipation pattern of quinalphos insecticide on mango (Mangifera indica L. cv. Neelum) fruits during the summer of 1995. Quinalphos was sprayed at 15-day intervals at rates of 0.05% and 0.1% by volume on mango when the fruits were at marble size stage. The average initial deposit of the quinalphos residues in mango fruit samples after the second application of quinalphos at a rate of 0.05% was found to be 3.76 parts per million (ppm) which was reduced to 0.14 ppm, 15 days after spraying with 96% dissipation. At the higher dose (0.10%), the initial deposit was 6.75 ppm at 0 day which was reduced to 0.23 ppm after 15 days with 97% dissipation. Hence, a waiting period of 11.5 days and 14.2 days after treatment, is required for the safe consumption of fruits at the recommended and double the recommended doses, respectively, before harvest.