Persistence and Metabolism of Fipronil in Sugarcane Leaves and Juice.

Fipronil gives effective control of early shoot borer and termites in sugarcane. The persistence and metabolism of fipronil in sugarcane leaves and juice were studied following application of fipronil (Regent 0.3 G) at 75 and 300 g a.i. ha. Samples of sugarcane leaves were collected at various time intervals. Samples of sugarcane juice were collected at harvest. Residues of fipronil and its metabolites were quantified by gas liquid chromatograph. The limit of quantification of fipronil and its metabolites was 0.01 mg kg for sugarcane leaves and juice. Total residues of fipronil and its metabolites in sugarcane leaves after 7 days of its application at 75 and 300 g a.i. ha were 0.26 and 0.66 mg kg, respectively. Residues could not be detected after 60 and 90 following fipronil application at either concentration. In sugarcane leaves, fipronil was found to be the main constituent, followed by its metabolites amide, desulfinyl, sulfone and sulfide. Samples of sugarcane juice did not reveal the presence of fipronil or its metabolites following its application at both the dosages at harvest. [ABSTRACT FROM AUTHOR]