Persistence of three newer insecticides on cabbage (Brassica oleracea L. Var. capitata)

Results of a field experiment conducted during the rabi season 2018–19 to determine the residue dynamics of three newer insecticides on cabbage, variety Pusa Cabbage-1, are reported. The average recovery values were calculated to be 88.97, 84.46 and 81.58 per cent, respectively for diafenthiuron, indoxacarb and novaluron. Novaluron showed minimum initial deposit of 0.218 mg kg⁻¹, followed by diafenthiuron (0.309 mg kg⁻¹) and indoxacarb (0.604 mg kg⁻¹) which were below their respective MRLs on cabbage. All the three insecticides were below their quantification limits on 7^th d after spray. The limits of quantification by HPLC for diafenthiuron, indoxacarb and novaluron were 0.0307, 0.0127 and 0.0158 mg kg⁻¹, respectively. The half-life values were 1.05, 1.73 and 1.14 d respectively for diafenthiuron, indoxacarb and novaluron, with their safe waiting periods of 0.77, 0.13 and 1.91 d respectively on cabbage heads.