软枝黄蝉提取物对螺旋粉虱的杀虫活性

室内和田间测定了软枝黄蝉提取物对螺旋粉虱的杀虫活性。结果表明，软枝黄蝉提取物对螺旋粉虱蛹的毒杀活性较差；对螺旋粉虱若虫具有很强的毒杀作用，其毒力回归方程为5.963 3＋1.349 0 x，LC50值为0.19 mg/mL；对螺旋粉虱成虫也具有显著的毒杀活性，其毒力回归方程为6.259 4＋1.520 5 x，LC50值为0.15 mg/mL，低于其对螺旋粉虱若虫的LC50值，显示其对成虫的杀虫活性更强。田间防治试验显示，软枝黄蝉提取物对螺旋粉虱具有较好的田间防治效果，1 mg/mL提取物药后3 d的防效

Insecticidal Activity of Extract from Allamanda cathartica Linn against Aleurodicus disperses Russell

Insecticidal activity of extract from Allamanda cathartica Linn against Aleurodicus disperses Russell were investigated in the laboratory and field. The results showed that the extract has no toxicity activity against the pupae of A. disperses Russell, while possessed a strong toxicity against the larvae of A. disperses Russell with linear regress equation of Y=5.963 3+1.349 0x and LC50 of 0.19 mg/mL. Insecticidal activity of extract against the adult of A. disperses Russell was enhanced compared to that of larvae of A. disperses Russell with a relatively lower LC50 of 0.15 mg/mL. Field experiments showed that the 1 mg/mL extract was highly effective in control of A. disperses Russell, and the corrected efficacy maintained at 83.40% when examined at 7th day after treatment. Extract of Allamanda cathartica Linn as a insecticide controlling A. disperses Russell is therefore promising.