Comparison between the toxicity of nano and bulk formulations of imidacloprid against wheat aphid, bird cherry-oat aphid, Rhopalosiphum padi L

Abstract

Recently, nano-insecticide formulations and new insecticide application methods are promised in pest control improvement. Wheat crop is infested by many sucking pests, such as cereal aphids in Upper Egypt. The toxicity of the recommended dose of imidacloprid (70% WS GAUCHO^®) as positive control, the full and half recommended dose of nano and bulk imidacloprid 25% WP (BEST^®) formulations were investigated under laboratory and field conditions against bird cherry-oat aphid, Rhopalosiphum padi L. The leaf-dip bioassay results indicated that the nano-imidacloprid formulations had higher potency ratio than the bulk formulations by 2.53 to 7.17 folds. Significant reduction percentage of aphids was recorded in seed treatments of field wheat crops, the aphid reductions reached 95% after 60 days. All insecticide treatments showed significant increasing in grain yield ranging from 10.55% to 22.02% higher than the control. The results concluded that the nano-imidacloprid formulation is promising formulation in cereal aphid control. Moreover, the seed-treatment is better than foliar treatment as a pest control tool for protecting the wheat seedling against sucking insect pests.