Dissipation and dietary risk assessment of imidacloprid and spiromesifen in brassica and fruiting vegetables following good agricultural practices

Field trials were conducted to study dissipation of imidacloprid and spiromesifen from vegetable and to carry out risk assessment. Method validation parameters were within the acceptable range with limit of quantitation (LOQ) of 0.05 mg kg⁻¹ for both the pesticides. Two foliar sprays of imidacloprid (Confidor 17.8 SL) @ 20 and 40 g ai ha⁻¹and spiromesifen (Oberon 22.9 SL) @ 96 and 192 g ai ha⁻¹ were applied at an interval of 10 days. The residues of imidacloprid were below LOQ (0.05 mg kg⁻¹) after 1 day in fruiting vegetables and on 5 to 7 days in other vegetables. Residues of spiromesifen reached below LOQ (0.05 mg kg⁻¹) on 10 to 20 days. Halflife ranged from 1.4 to 3.9 for imidacloprid and 2.3 to 6.7 days for spiromesifen. Hazard Quotient (HQ) was <1, suggesting that it is safe to use imidacloprid and spiromesifen in/on vegetable crops.