Persistence of insecticides in ready-mix formulations and their efficacy against Lipaphis erysimi (Kalt) in cauliflower

Persistence of cypermethrin, deltamethrin, profenofos, and triazophos in cauliflower curd was studied, following application of two premix formulations viz: Roket 44EC (profenofos 40 % + cypermethrin 4 %) and Anaconda Plus 36EC (triazophos 35 % + deltamethrin 1 %) at recommended (1.0 L ha −1 ) and double doses (2.0 L ha −1 ). In the case of Roket 44EC, residues of cypermethrin dissipated with the half-life values of 1.5–2.1 days, whereas residues of profenofos dissipated with the half-life of 2.9–3.3 days on cauliflower curd. In the case of Anaconda, residues of triazophos and deltamethrin dissipated from curd with the half-life values of 2.6–3.0 and 2.2–2.6 days, respectively. Both the combination mix significantly reduced the aphid population up to 14 days after spray and increased the yield by 155–160 % over control. Anaconda (2.0 L ha −1 ) treated plots yielded the highest number of marketable curds. Based on risk assessment analysis, safe waiting period of 3 and 5 days has been suggested for Roket 44EC and Anaconda Plus 36EC, respectively, in cauliflower at recommended dose of application.