Effect of light and pH on persistence of flubendiamide.

Persistence of flubendiamide in soil as affected by UV and sunlight exposure and in water as affected by pH was studied. At field capacity moisture regime, soil was treated with flubendiamide and exposed to UV and sunlight. Dissipation for the pesticide followed mono-phasic first order kinetics. Residues of flubendiamide, as thin film on petri-plates and soil thin film, dissipated with half-lives of 7.0 and 9.1 days under UV light and 12.0 and 19.1 days under sunlight, respectively. Residues of flubendiamide dissipated faster under UV light as compared to sunlight. Persistence study in aqueous medium under different pH condition indicated that flubendiamide residues persisted in water beyond 250 days with half-lives ranging from 250.8 to 301.0 days. Dissipation in water was faster at pH 4.0 (T(1/2) 250.8 days), followed by pH 9.2 (T(1/2) 273.6 days) and 7.0 (T(1/2) 301.0 days).