斜纹夜蛾核型多角体病毒的分离及感染力测定

对福建农业大学生物技术中心采集分离的斜纹夜蛾核型多角体病毒进行了致病过程和形态大小的观察、感染力测定以及小菜蛾和菜青虫对该病毒的敏感性等方面的初步研究．斜纹夜蛾核型多角体病毒形状不规则，大小不一，直径为１．０～２．５μｍ，平均直径为１．６５μｍ．以斜纹夜蛾、小菜蛾和菜青虫为靶标害虫，对该病毒的感染力及杀虫特异性进行了测定．结果表明：在测定的浓度范围内，斜纹夜蛾幼虫感病死亡率随多角体浓度和虫龄而变化，在２５℃下，３龄幼虫的致死中浓度为１×１０５．１４ＰＩＢｍＬ－１；浓度相同时，幼虫死亡速度随龄期增大而减慢；对小菜蛾和菜青虫幼虫的致病死亡率为０．可见，此多角体病毒对斜纹夜蛾具有较高的毒力，且专化性强．

Isolation and infection tests on Prodenia litura nuclear polyhedrosis virus

Some characteristics,　including morphology,　toxicity and specificity of Prodenia litura nuclear polyhedrosis virus (PLNPV) which was isolated from a dead larva of P.litura on a soybean leaf, were revealed. Symptoms of the host was described. It was observed that the polyhedra were irregular in shape, and their diameters ranged from 1.0　μm to 2.5 μm, mostly 1.65 μm. Tests of infection were carried out through using different instars of insects and different densities of the virus. The results showed that the mortality of the treated larvae depends on the densities of the virus and the larval instars. The LC50 for the third instar larvae at 25℃ was 1×105.14 PIB·mL-1. Sensitivities of both insects of Pieris rapae and Plutella xylostella to the virus was also detected, which showed that PLNPV is highly toxic and specific to its host.