In the present work, persistence and degradation of cyantraniliprole, a leading anthranilic diamide pesticide against sucking insect pests, in inceptisol soil has been studied. Effect of various factors like light source (UV-light, sunlight and dark), temperature (5, 25 and 37 °C), moisture regime (dry, field capacity and submerged) and carbon dioxide level (415 and 625 µL L-1) on dissipation was also evaluated. Formation of IN-J9Z38, a major metabolite of cyantraniliprole, was monitored in different treatments. Samples were processed as per QuEChERS method and analysis was done by HPLC-PDA. Matrix matched calibration curve, prepared in the range 0.001-10 mg L-1, indicated very good linearity (R2 > 0.99) and sensitivity (instrument limit of detection 0.001 mg L-1). Cyantraniliprole residues dissipated with time and 47.7%-98.8% dissipation was recorded on 90th day in different treatments. Minimum half-life of cyantraniliprole, i.e. 8.7 days was recorded at elevated CO2 level (625 ± 5 µL L-1) while its maximum half-life of 86.6 days was recorded at 5 °C. Metabolite IN-J9Z38 started forming from zero-day and reached the maximum on 15th to 60th day. Microbial biomass carbon, as an index of microbial activity of soil, correlated well with the degradation of cyantraniliprole.
Keywords: Abiotic factors; IN-J9Z38; cyantraniliprole; microbial biomass; soil degradation.