昆虫病原线虫对腰果云翅斑螟的室内致病力

摘要

研究了小卷蛾斯氏线虫 Steinernema carpocapsae All 品系、Biosys 品系，格氏斯氏线虫 S．glaseri NC52品系，长尾斯氏线虫 S．longicaudum X-7品系，嗜菌异小杆线虫 Heterorhabditis bacteriophora H06品系和印度异小杆线虫 H．indica LN2品系6个昆虫病原线虫品系在室内对腰果云翅斑螟 Nephopteryx sp．幼虫的致病力。结果表明，除了嗜菌异小杆线虫，其他参试线虫对腰果云翅斑螟3龄幼虫均具有较高的致病力，致死率80．0％～95．0％，各处理差异不显著。嗜菌异小杆线虫对腰果云翅斑螟幼虫控制效果最差，显著低于其他参试线虫。选择小卷蛾斯氏线虫 All 品系进一步研究其对腰果云翅斑螟的致病效果，结果发现，其对腰果云翅斑螟3龄幼虫处理24 h 后的LC50为22．94 IJs／头。处理24 h，小卷蛾斯氏线虫 All 品系对1～3龄幼虫的致死率（72．5％～84．7％）显著高于4～5龄幼虫（15．0％～30．0％）；处理120 h，对蛹的致死率仅为20．0％。研究表明，小卷蛾斯氏线虫 All 品系对腰果云翅斑螟低龄幼虫在室内具有一定控制潜力。%The virulence of six entomopathogenic nematodes (EPNs)strains of the families Steinernematidae and Heterorhabditidae was tested against the larvae of cashew nut borer Nephopteryx sp.in laboratory.The tested nematode strains included Steinernema carpocapsae All,S .carpocapsae Biosys,S .glaseri NC52,S .longicaudum X-7,Heterorhabditis bacteriophora H06 and H .indica LN2.The results showed that,except H .bacteriophora H06,the other nematode strains were highly virulent to the 3rd instar larvae of Nephopteryx sp.,with the mortal-ity of 80.0%-95.0% and no significant differences among the strains.Minimum mortality was observed when treated with H .bacteriophora H06,which significantly lower than that with other nematode strains.Based on the above results,the strain S .carpocapsae All was selected for the subsequent bioassay.Laboratory bioassay demon-strated that the LC50 value of strain S .carpocapsae All against the 3rd instar larvae exposed for 24 h was 22.94 IJs per individual.After 24 h exposure to S .carpocapsae All,the mortalities of the 1st,2nd and 3rd instar larvae (72.5%-84.7%)were significantly higher than those of the 4th and 5th instar larvae (15.0%-30.0%),while the mortality of pupa was only 20% after 120 h exposure.The above result indicated that the nematode strain S .carpocapsae All had some control effect on the lower instar larvae of Nephopteryx sp.in laboratory.