昆虫病原线虫对恩施地区银杏蛴螬的致病性研究

Pathogenicity of Entomopathogenic Nematodes to Ginkgo Grubs in Enshi Area

【目的】探寻利用昆虫病原线虫防治恩施地区银杏蛴螬可行性。【方法】从恩施地区银杏GAP基地采集、分离昆虫病原线虫,并测定其在不同条件下对银杏蛴螬的致病力。【结果】本研究共分离到2种昆虫病原线虫,经形态学鉴定分别为斯氏线虫(Steinernema carpocapsae)和嗜菌异小杆线虫(Heterorhabditis bacteriophora)。对银杏蛴螬铜绿丽金龟(Anomala corpulenta)幼虫的侵染结果表明,侵染96 h和120 h后,斯氏线虫导致的校正死亡率分别为61.67%和86.67%,而嗜菌异小杆线虫导致的校正死亡率分别为46.67%和61.67%,相对较低。进一步对影响斯氏线虫致病力的单因子测定发现,侵染120 h后,当侵染剂量为300 IJs/mL、侵染温度为25℃、土壤湿度为18%时,斯氏线虫导致铜绿丽金龟幼虫的死亡率均为最高值,分别为98.33%、96.67%和93.33%,明显高于其它侵染处理组。【结论】斯氏线虫对蛴螬幼虫的致病力显著高于嗜菌异小杆线虫;在侵染剂量为300 IJs/mL、温度为25℃及土壤湿度为18%等条件下,斯氏线虫对铜绿丽金龟幼虫致病力最强。

【Objective】Explore the feasibility of using entomopathogenic nematodes to control ginkgo grubs in Enshi area.【Method】Entomopathogenic nematodes were collected and isolated from Ginkgo GAP base in Enshi area,and their pathogenicity to ginkgo grubs under different conditions was evaluated.【Result】In this study,two species of entomopathogenic nematodeswere successfully isolated and identified as S.carpocapsae and H.bacteriophora by morphology.The results of infection after 96 hours and 120 hours showed that the adjusted mortality of S.carpocapsae to A.corpulenta larvae were 61.67%and 86.67%respectively,while it was a little lower than that of H.bacteriophora to A.cor⁃pulenta larvae,which were 46.67%and 61.67%respectively.Further measurements of single-factor measurements affecting the pathogenicity of S.carpocapsae revealedthat after 120 hoursof infestation,when the infestation dose was 300 IJs/mL,the infestation temperature was 25℃,and the soil moisture was 18%,the mortality rates of S.carpocapsae to A.corpulenta larvae were the highest,which were 98.33%,96.67%,and 93.33%respectively,significantly higher than the other infestation treatment groups.【Conclusion】The pathogenicity of S.carpocapsae to A.corpulenta larva was significantly higher than that of H.bacteriophora.The pathogenicity of S.carpocapsae to A.corpulenta wasthe strongest under the conditions of 300 IJs/mL infestation dose,25℃and 18%soil humidity.