Persistence of Trifloxystrobin and Tebuconazole in Cowpea Following Application of Combination Formulation

A supervised field trial of was conducted to estimate the residues of trifloxystrobin, its metabolite CGA 321113 and tebuconazole in cowpea after application of Nativo WG (trifloxystrobin 25% + tebuconazole 50%) @ 350 and 700 g ha⁻¹. After last application, green pods were collected separately at different time intervals and processed following QuEChERS methodology. Residues of trifloxystrobin and tebuconazole were quantified by gas liquid chromatography and gas chromatography-mass spectrometry, respectively. The residues were found to be below LOQ (<0.05 mg kg⁻¹) at 5 and 7 days for trifloxystrobin, and 10 days for tebuconazole, respectively, for recommended and double the recommended doses. The half-life values on green pods were 1.07 and 1.13 days for trifloxystrobin and 1.30 and 1.29 days for tebuconazole. A waiting period of 1 day should be followed for consumption of immature pods.