Dissipation kinetics of flubendiamide and thiacloprid on tomato (Lycopersicon esculentum Mill) and soil

Abstract

Introduction Flubendiamide, a phthalic acid diamide widely used against the lepidopteran pests and thiacloprid, the first chloronicotinyl insecticide quite effective against the sucking insects, white flies and jassids have recently been used on various vegetable crops in India. Objectives Studies on dissipation kinetics of insecticides is very essential to work out their half- lives and waiting periods for the safe consumption of agricultural produce. Methods Standardized methodology supported by recovery studies is adopted to estimate residues of flubendiamide and thiacloprid on tomato. Final estimation of residues was accomplished using high performance liquid chromatography by employing C18 column and photo diode array at 230 wavelength. Results Half-lives values for flubendiamide following its three applications at 10 days intervals @ 48 g a.i. ha−1 were observed to be 0.33 and 1.00 days, respectively. Similarly, at the same application rate these values for thiacloprid were found to be 1.18 and 0.95 days, respectively. Flubendiamide and thiacloprid residues were observed to dissipate below their determination limit of 0.01 mg kg−1 after 3 and 5 days, respectively, when applied @ 48 g a.i.ha−1. Soil samples collected after 15 days did not show the presence of flubendiamide, desiodo flubendiamide, and thiacloprid at their determination limit of 0.01 mg kg−1. Conclusion A waiting period of 5 days is recommended for safe consumption of tomato fruit after application of combination formulation of flubendiamide 24%+thiacloprid 24% (480 SC) @ 200 g ha−1.