从广西部分地区采集到自然罹病死亡的疑似具有病毒症状的斜纹夜蛾幼虫,对其进行病毒的分离鉴定。用研磨病虫尸体得到的浆液,经分离纯化后感染连续人工饲养至第三代的健康斜纹夜蛾三龄幼虫,部分样品能诱发病毒病症状。经差速离心的提纯物,在相差显微镜下观察到外形不规则的颗粒,进一步在电镜下观察到菱形、五边型、六边形、近似圆形等形状的多角体。用依据Splt NPV DNA的egt基因保守序列设计的引物,对多角体中提取的DNA进行PCR扩增,得到了与预期一致的3 80 bp片段。经测序分析,该PCR片段与Splt NPV egt基因在核苷酸水平上的同源性为99.4%,演绎的氨基酸水平上的同源性为1 0 0 %。进一步对采自广西1 6个地域的疑似具有病毒症状的2 0 0份斜纹夜蛾幼虫样本进行PCR扩增,其中6个地域的62份样本呈PCR阳性,这表明,广西斜纹夜蛾自然种群中存在着Splt NPV的流行 Viruses were isolated and identified from Spodoptera litura larvae, suspected of being virus-like, from natural disasters in parts of Guangxi. The slime obtained from grinding diseased worms was isolated and purified and infected with third-instar larvae of healthy Spodoptera litura, which were fed on to the third generation continuously, some of which could induce symptoms of viral diseases. After differential centrifugation, irregularly shaped particles were observed under a phase contrast microscope, and further rhombus, pentagonal, hexagonal, and approximately circular polygonal bodies were observed under an electron microscope. With the primers designed according to the conserved sequence of egt gene of Splt NPV DNA, the amplified DNA was amplified by PCR, and the expected 380 bp fragment was obtained. The nucleotide sequence of the PCR fragment was identical to the Splt NPV egt gene by 99.4% sequence analysis and deduced amino acid sequence homology of 100%. Further, PCR amplification was carried out on 260 samples of suspected Sporadisia larvae collected from 16 areas in Guangxi, of which 62 samples were PCR positive in 6 regions, indicating that natural populations of Spodoptera exigua There is a prevalence of Splt NPV