印楝素和藜芦碱对昆虫病原线虫存活及感染力的影响

Effects of azadirachtin and veratrine on the survival and infectivity of entomopathogenic nematodes

测定了两种植物源杀虫剂印楝素、藜芦碱和对照杀虫剂高效氯氟氰菊酯在不同使用量下处理Heterorhabditis indica LN2,H.indica 212-2,Steinernema carpocapsae All和S.pakistanense 94-1等4个昆虫病原线虫品系2 d、1 w、2 w、3 w和4 w后对线虫存活和感染力的影响。3种杀虫剂对H.indica LN2和S.pakistanense 94-1存活的影响最小,藜芦碱和高效氯氟氰菊酯对H.indica 212-2存活的影响小于对S.carpocapsae All存活的影响,印楝素则对S.carpocapsae All存活的影响小于对H.indica 212-2存活的影响。藜芦碱和高效氯氟氰菊酯处理后线虫死亡率低于10%,对存活线虫对大蜡螟的感染力没有显著影响。印楝素在高使用量(8.10 g/ha)下对线虫的致死作用明显,且处理时间在3 w以上时显著提高线虫的死亡率,但是在田间推荐使用量(4.05 g/ha)及稀释使用量下对线虫的存活及感染力没有显著影响。结果表明,印楝素和藜芦碱以及对照药剂均可与4个品系的线虫共同施用于田间用于农业害虫的综合防控。

The effects of three insecticides at different application rates on survival and infectivity of four entomopathogenic nematode isolates, Heterorhabditis indica LN2, H. indica 212-2, Steinernema carpocapsae All and S. pakistanense 94-1 , for different periods were evaluated in this study. H. indica LN2 and S. pakistanense 94-1 showed lower mortality rates than the other two nematode isolates after treated by the three insecticides. Mortality rates of H. indica 212-2 treated by veratrine and λ-cyhalothrin were lower than that of S. carpocapsae All, while mortality rates of H. indica 212-2 treated by azadirachtin were higher than that of S. carpocapsae All. Corrected mortality rates of the nematodes treated by veratrine andλ-cyhalothrin were lower than 10% and the surviving nematodes retained their infectivity to the Galleria larvae. When azadirachtin was applied at high rate of 0. 810 mg/m2 and for treated periods of longer than 3 weeks, mortality rates of the nematodes were significantly increased. But when azadirachtin was applied at 0. 405 mg/m2 and lower rates, survival and infectivity of the nematodes were not significantly affected. Our results showed that the three tested insecticides could be combined with the four isolates of entomopathogenic nematode in the field to control important agricultural insect pests.