National Center for Agricultural Utilization Research, USDA-ARS, 1815 N. University Ave., Peoria, IL 61604-3902, United States.
J Invertebr Pathol. 2012 Feb;109(2):194-200. doi: 10.1016/j.jip.2011.11.002. Epub 2011 Nov 12.
Three biopesticide parameters were evaluated for a fast-killing isolate (3AP2) and a wild-type isolate (Sf3) of Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV). Both isolates were evaluated for virus production using in vivo methods, for speed of kill based on bioassay of applications to glasshouse-grown and field-grown plants, and for residual insecticidal activity of unformulated virus and an encapsulating formulation to provide UV protection. Two inoculation rates comparing relative in vivo production of the isolates demonstrated 3AP2 inoculated larvae were significantly smaller than Sf3 inoculated larvae at death. At the lower inoculation rate, Sf3 inoculated larvae produced approximately twofold more occlusion bodies as the 3AP2 inoculated larvae. A model system of applications to cabbage plants and a bioassay to observe mortality of neonate S. frugiperda (J.E. Smith) after feeding on samples of treated leaves was used to evaluate speed of kill and residual insecticidal activity. The LT(50) for the 3AP2 isolate was at least 30 h less than the LT(50) for the Sf3 isolate when applied to either glasshouse-grown or field-grown plants. The spray-dried lignin encapsulating formulation provided similar benefits to both virus isolates when exposed to simulated sunlight in the laboratory and to natural sunlight in the field. For treatment applications to field grown cabbage in June, the half-life for efficacy of unformulated virus was <7.5 h compared with a half-life of >26.7 h for encapsulated virus. These results demonstrate that improved technologies can be combined to address characteristics which otherwise can limit the commercial potential of microbial-based biological insecticides.
三种生物农药参数用于评价斜纹夜蛾多粒包埋型核型多角体病毒（SfMNPV）的快速致死分离株（3AP2）和野生型分离株（Sf3）。通过体内方法评估了两种分离株的病毒产量，通过玻璃温室和田间植物的生物测定评估了快速致死速度，并评估了未配制病毒和含有紫外线保护剂的包封制剂的残留杀虫活性。两种接种率比较了两种分离株的体内相对产量，结果表明，3AP2 接种的幼虫在死亡时明显小于 Sf3 接种的幼虫。在较低的接种率下，Sf3 接种的幼虫产生的包埋体数量大约是 3AP2 接种的幼虫的两倍。将其应用于甘蓝植株的模型系统和观察取食处理叶片的新孵化斜纹夜蛾（J.E. Smith）死亡率的生物测定，用于评估快速致死速度和残留杀虫活性。当应用于温室或田间种植的植物时，3AP2 分离株的 LT(50)至少比 Sf3 分离株的 LT(50)短 30 小时。在实验室模拟阳光和田间自然阳光暴露下，喷雾干燥木质素包封制剂对两种病毒分离株均提供了类似的好处。对于 6 月田间种植的甘蓝的处理应用，未配制病毒的功效半衰期<7.5 小时，而包封病毒的半衰期>26.7 小时。这些结果表明，可以结合改进的技术来解决可能限制微生物基生物杀虫剂商业潜力的特征。
