Persistence of Combination Formulation of Flubendiamide + Thiacloprid in/on Cucumber under Sub-tropical Climate of North India

Dissipation of a mixed formulation of flubendiamide 240 + thiacloprid 240 SC (w/v) applied @ 60 and 120 g a.i. ha⁻¹ on cucumber fruits to work out the half lives and waiting periods of both the components of the formulation for a safe consumption of cucumber is reported. The residues of flubendiamide and thiacloprid were processed as per QuEChERS method and quantified by HPLC equipped with PDA detector. The half-lives of 1.61 to 2.09 d for total flubendiamide; 2.09 and 2.18 for thiacloprid @ 60 and 120 g a.i. ha⁻¹ respectively were worked out. Flubendiamide and thiacloprid residues dissipated to below their determination limit of 0.05 mg kg⁻¹ at 10 and 5 d respectively, when applied @ 60 g a.i. ha⁻¹. Soil samples collected at 20 d of application did not show the presence of flubendiamide, des-iodo flubendiamide and thiacloprid at their determination limit of 0.05 mg kg⁻¹. A pre harvest interval of 7 d is suggested at the recommended dosage.