影响天幕毛虫核多角体病毒感染力的若干因子

Some Factors Affecting Infectivity of Nuclear Polyhedrosis Virus of the Tent Caterpillar, Malacosoma neustria testacea M.

测定几种理化及生物因子对天幕毛虫感染力的影响。结果表明,被感染的幼虫龄期越小,对病毒越敏感,1～2龄幼虫感染率在95％以上,5龄幼虫基本不感病。在18℃以下的温度,幼虫不感受病毒的侵染,24～27℃幼虫发病率最高。涂在叶子表面的病毒多角体经紫外线照射60min,其活性丧失50％以上,照射120min,病毒活性基本丧失竭尽。病毒液喷在果树的向阳面比喷在阴面感染力丧失得快。提纯的多角体干粉、多角体悬液分别在冰箱中保存2～3a,其感染力没有变化,风干的虫尸,无论在冰箱里或在窒温下,经一年保藏,感染力有较大的下降。粗提纯的多角体与虫尸悬液比较,其感染力没有显著差异。

Some physical and chemical factors affecting MntNPV infectivity were studied. The resuts showed that the minor instar of inffected larva was, the more sensitive to MntNPV it was. Infectivity rate of the larvae at 1～3 instar was over 95%, while the larvae at 5 instar were not likely infected. The larvae were not infected by the virus below 18℃. At 24～27℃ infectiity rate of the larvae was the maximum. After the polyhedra coated on leaf surface were radiated by ultraviolet ray for 60 minetes, over 50% of their activity was lost; radiated for 120 minetes all of their activity was lost. The infectivity of the virus solution sprayed on the sunlit side of fruit tree was lost sooner than that of the sunless side of the tree. Infectivity of partially purified dry polyhedron powder, polyhedron suspension and dead worm suspension stored in refrigerator for 2～3 years were not changed. The infectivity of air dried dead worm stored for 1 year decreased greatly, regarolless whethe it was in refrigerator or in room temperature. The infectivity of partially purified polyhedra does not has significant difference from the dead worm suspension.