Efficacy of Two Neonicotinoids against Mustard Aphid, Lipaphis erysimi (Kalt.) and their Toxicity to Honey Bee, Apis cerana F.

Evaluation of the efficacy of imidacloprid @ 20, 40 and 60 g a.i. ha⁻¹) and thiacloprid @ 15, 30 and 45 g a.i. ha¹ alongwith deltamethrin @ 15 g a.i. ha⁻¹ as standard check against mustard aphid, Lipaphis erysimi (Kalt.) and their toxicity to honey bees, Apis cerana F. on rape seed crop (TS-36) in the apiary of Assam Agricultural University, Jorhat, India during 2010–11 and 2011–12 revealed maximum reduction of L. erysimi population with imidaclorprid at 60 g ai ha⁻¹ and thiacloprid at 45 g ai ha⁻¹ followed by imidaclorprid 40 g ai ha⁻¹ and thiacloprid 30 g ai ha⁻¹ and deltamethrin 15 g ai ha⁻¹ as check. Maximum bee mortality was found in six hours with imidacloprid 60 g ai ha⁻¹ followed by imidacloprid 40 g ai ha⁻¹, thiacloprid 40 g ai ha⁻¹, thiacloprid 30 g ai ha⁻¹ and deltamethrin 15 g ai ha⁻¹. The optimum increase in yield of rapeseed was obtained with the treatment of imidacloprid 40 g ai ha⁻¹ (33.54%) followed by thiacloprid 30 g ai ha⁻¹ (18.78%) and deltamethrin 15 g ai ha⁻¹ (17.90%) against (7.93%) in control.