Toxicity of Synergistic Imidacloprid to Aphis craccivora Koch

[Aims] Toxicity of synergistic imidacloprid to Aphis craccivora Koch was studied.[Methods] The 24 h-lethal effect of synergistic imidacloprid were determined by impregnation method,and the commercial imidacloprid 35% sc as control.[Results] The results showed that synergistic imidacloprid SE-6-4 31% SC had the highest control efficacy with lc50 of 5.267 3 mg/l,followed by synergistic imidacloprid se-1 31% sc with lc50 of 7.744 1 mg/l.The lc50of imidacloprid 35% sc was 10.563 0 mg/l,and had low toxicity to Aphis craccivora Koch.[Conclusions] The control efficacy of low-dose synergistic imidacloprid SE-6-4 and SE-1 31% SC were similar to that of high-dose imidacloprid 35% SC.They were good formulations and could be used in field trials.