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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.

An analytical method was standardized for the estimation of residues of flubendiamide and its metabolite desiodo flubendiamide in various substrates comprising cabbage, tomato, pigeonpea grain, pigeonpea straw, pigeonpea shell, chilli, and soil. The samples were extracted with acetonitrile, diluted with brine solution, and partitioned into chloroform, dried over anhydrous sodium sulfate, and treated with 500 mg of activated charcoal powder. Final clear extracts were concentrated under vacuum and reconstituted into HPLC grade acetonitrile, and residues were estimated using HPLC equipped with a UV detector at 230 lambda and a C18 column. Acetonitrile/water (60:40 v/v) at 1 mL/min was used as mobile phase. Both flubendiamide and desiodo flubendiamide presented distinct peaks at retention times of 11.07 and 7.99 min, respectively. Consistent recoveries ranging from 85 to 99% for both compounds were observed when samples were spiked at 0.10 and 0.20 mg/kg levels. The limit of quantification of the method was worked out to be 0.01 mg/kg.

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