Fate of fipronil in cotton and soil under tropical climatic conditions.

Field study was carried out to investigate fate of fipronil (Regent 0.3G) in cotton and soil applied at the time of sowing of cotton crop (Variety: H-1117)@56 (T₁) and 112 g a.i.ha⁻¹ (T₂) during kharif season (summer season, from April to November) 2006-07. The residues of fipronil in both the doses dissipated almost completely with in 90 days. Kinetic studies revealed that dissipation of fipronil followed first order kinetics with half-life period of 23.35 days in single dose and 24.31 days in double dose. At the time of harvest, residues in soil, cotton lint and seed were below the quantifiable limit of 0.01 mg kg⁻¹.