Simultaneous Determination of Residual Behavior, Dissipation Kinetics, and Dietary Risk Assessment of...

The insect pests of green gram (Vigna radiata L.) can be effectively managed by the combined formulation of chlorantraniliprole 9.3% w/w + lambda cyhalothrin 4.6% w/w (ZC). These affect nervous system of the target pests. The potential of these pesticides to persist in the edible commodities and cause adverse effect to human health and environment necessitate the study of residual behavior. Therefore residue and persistence of chlorantraniliprole and lambda cyhalothrin was investigated in field trials of green gram crop following two foliar sprays at application rates of 35 and 43.75 g a.i. ha^-1 (X and 1.25X dose, respectively). The samples, after processing at Pesticide Residue Analysis Laboratory, Ludhiana were subjected to LCMS-MS and GC-MS/MS for quantification of chlorantraniliprole and lambda cyhalothrin, respectively. In immature green gram pods, average initial deposits of chlorantraniliprole were 0.45 and 0.64 mg kg^-1 that declined to levels below the limit of quantification (< 0.03 mg kg^-1) by the 15^th day after application. Average initial lambda cyhalothrin deposits in immature green pods were 0.05 and 0.09 mg kg^-1 dissipating rapidly to concentrations below its quantification limit (0.01 mg kg^-1) by the fifth day for both application rates. The residues were below quantification limit in mature pods, straw and soil samples taken at harvest. First order kinetics for dissipation was observed with t_1/2 values of chlorantraniliprole as 2.61 and 3.44 days and lambda cyhalothrin as 2.44 and 2.93 at X and 1.25X dosages, respectively.