Dynamic Dissipation Pattern and Pre-harvest Interval Prediction of Spirotetramat in Tomato and Onion under Field Conditions

Results on spirotetramat dissipation on tomato and onion in field using quick, easy, cheap, effective, rugged and safe (QuEChERS) procedure combined with liquid chromatography-ultra violet detector are reported. The lowest recovery in fortified samples was found to be 79 per cent with relative standard deviations (RSDs) ≤ 15.9 per cent for the three substrates (tomato or onion, soil and water).Spirotetramat dissipated relatively quickly following first-order kinetics with a half-life of 7.34 d in tomatoes and 1.23 d in onion. The insecticide reached below MRL in 7 d in tomato (MRL: 2 mgkg−1) and 3 d in onion (MRL: 0.4 mgkg−1). Pre-harvest intervals (PHI) of 7 and 3 d for spirotetramat in tomatoes and onion respectively are suggested. Distribution of the pesticide around the crop environments is also reported.