Dissipation of Insecticidal Residues having Different Modes of Action in Cabbage

The dissipation study of residues of insecticides having different modes of action was studied in cabbage. The insecticides such as deltamethrin, chlorantraniliprole and fipronil residues were sprayed as foliar application twice at an interval of 7 days with the recommended doses of deltamethrin (@ 12.5 g a.i./ha), chlorantraniliprole (@ 30 g a.i./ha) and fipronil (50 g a.i./ha). The samples were taken randomly before the application of any insecticides and 1 hour after the second spray of insecticides. The residues were below the detectable limit for all the insecticides. The residues of fipronil were found to be more persistent than those of chlorantraniliprole and deltamethrin. Fipronil was found to persist up to the 7 th day with a residue of 0.01 mg kg -1 . However, the residues of chlorantraniliprole and deltamethrin persisted upto the 5 th day i.e. 0.11 mg kg -1 and 0.03 mg kg -1 respectively. Observation revealed that the residues of chlorantraniliprole on cabbage head dissipated over the course of time and an equally high degree of dissipation was observed. The half-life of chlorantraniliprole was found to be 1.81 days as compared to 1.07 and 1.42 days respectively for fipronil and deltamethrin.