Residual dynamics and ecological risk assessment of indoxacarb in Ipomoea aquatica

The residual levels and dissipation rate of indoxacarb in Ipomoea aquatica were determined by UPLC-MS/MS. 30% indoxacarb suspension was sprayed at recommended doses of 45 and 67.5 g ai/ha on the leaf of Ipomoea aquatica at six geographically distant experimental sits, Changsha, Nanning, Jiyuan, Hangzhou, Qingdao, Shijiazhuang in China. Samples were collected randomly in triplicates at 2h、1d、3d、5d、7d、10d、14d、21d、28d intervals after insecticide application. The residues were found to have half-lives of 2.61–3.67d. Indoxacarb was detectable in Ipomoea aquatica harvested after intervals of 5, 7 and 10 days. We recommend that the harvest interval should be longer than 10 days after spraying 30% SC.