Persistence of Combination-Mix (β-Cyfluthrin + Imidacloprid) on Tomato (Lycopersicon esculentum)

Field and laboratory experiments were carried out to evaluate the persistence of combination-mix (p-cyfluthrin + imidacloprid) on tomato (Lycopersicon esculentum). The initial deposit of p-cyfluthrin ranged from 0.99–2.13 mg kg⁻¹. The results of persistence studies showed that β-cyfluthrin was detectable only up to 7 days after application from β-cyfluthrin alone formulation, but it persisted up to 10 days from lower rate of application from combination mix (80 g ai ha⁻¹). The half-life values of β-cyfluthrin residues ranged from 2.0–2.7 days. The initial deposit of imidacloprid on tomato ranged from 1.33–2.38 mg kg⁻¹. The comparison of dissipation of imidacloprid residues from combination-mix and from individual formulation indicated that imidacloprid in individual formulation persisted up to 10 days, whereas it persisted up to 15 days. The half life values of imidacloprid residues from tomato were 1.9–2.7 days from all the treatments.