Persistence of insecticide residues on muskmelon and their safety constants

The persistence and dissipation of endosulfan, monocrotophos and dimethoate alongwith synthetic pyrethroids, fenvalerate and cypermethrin were studied in/on muskemelon fruits following foliar applications at fruiting stage of the crop. The residues of endosulfan, monocrotophos and dimethoate persisted for 10 to 15 days on fruit surface and also made their way into the fruit pulp due to their absorption. Accordingly, the treatments required waiting periods of 2 to 5 days; 16 to 20 days and 1 to 4 days for endosulfan, monocrotophos and dimethoate, respectively for their residues to reduce to safe levels. Synthetic pyrethroids, fenvalerate and cypermethrin persisted for 7 to 10 days on fruit surface only and required waiting periods of 7 to 11 days for reduction of bioconcentration of residues to safe limits. Peeling off fruit skin dislodged substantial amont of insecticide residues.