Residues of synthetic pyrethroid insecticides on horticultural crops

Abstract

AbstractFoliar applications of synthetic pyrethroids were made to several crops to determine residue levels at various intervals after application. On onions, residues of cypermethrin, permethrin and fenvalerate were negligible > 0.1 mg kg−1, 7 days after application. On lettuce, residues of fenvalerate and permethrin were 0.8 mg kg−1. On celery, residues of fenvalerate did not decline and ranged from 0.12 to 0.25 mg kg−1 during the 14‐day period. On green bush‐beans, residues of permethrin and cypermethrin did not decline during the 14‐day period and ranged from 0.1 to 0.6 mg kg−1. By day 7, residues of cyfluthrin, cypermethrin, deltamethrin, fenvalerate and permethrin on strawberries were less than the acceptable maximum tolerance of 0.1 mg kg−1 with the exception of cypermethrin, applied at the rate of 0.14 kg a.i. ha−1 which gave a residue of 0.14 mg kg−1.