4种植物源杀虫剂对葡萄蓟马的致毒作用

为探讨植物源杀虫剂对烟蓟马的毒力、生长发育和繁殖的影响，采用浸叶法测定4种植物源杀虫剂对烟蓟马2龄若虫和成虫的毒力，分析亚致死浓度对2龄若虫生长发育和繁殖的影响。结果表明：印楝素和苦参碱对2龄若虫的毒力相对较高，LC₅₀分别为6.983 mg/L和9.571 mg/L。印楝素、苦参碱和鱼藤酮的亚致死浓度LC₄₀对2龄若虫期和蛹期有显著延长作用，对化蛹率、羽化率、单雌产卵量和卵孵化率有明显地抑制作用。印楝素LC₄₀对化蛹率、羽化率、单雌产卵量和卵孵化率的抑制作用最强，抑制率分别为23.64%、17.60%、18.37%和12.54%。说明印楝素和苦参碱对烟蓟马的致毒作用较好，低龄若虫（2龄期前）是防治的最佳时期，除发挥2种药剂的毒力外，还可通过亚致死浓度对存活若虫的生长发育和繁殖形成抑制作用。

Toxicity Effect of Four Botanical Insecticides against Grape Thrips

Trips tabaci is an important pest in grapes, in order to explore the toxicity, growth and fecundity of botanical insecticide on T.tabaci, the toxicity of four botanical insecticides on 2nd nymph and adult were evaluated by leaf dipping method, and the effect of sublethal concentration on growth and fecundity of 2nd nymph were analyzed. The results showed that azadirachtin and matrine had relatively high toxicity to 2nd nymph, and the median lethal concentration (LC₅₀) was 6.983 mg/L and 9.571 mg/L, respectively. The sublethal concentration (LC₄₀) of azadirachtin, matrine and rotenone had significant prolongation effect on 2nd nymph stage and pupal stage, and pupation rate, eclosion rate, number of eggs laid per female and egg hatch rate were significantly inhibited. The sublethal concentration (LC₄₀) of azadirachtin had the strongest inhibition on pupation rate, eclosion rate, number of eggs laid per female and egg hatch rate, with inhibition ratio of 23.64%, 17.60%, 18.37% and 12.54%, respectively. These results indicated that the azadirachtin and matrine had better toxicity to Trips tabaci, and the young nymph (before 2nd nymph) was the best time for control, in addition to exerting the toxicity of two botanical insecticides, sublethal concentration could also inhibit the growth and fecundity of the surviving nymph.