The fall armyworm, Spodoptera frugiperda (JE Smith) is a key pest in the Americas. Control strategies are mainly carried out by use of chemical insecticides and transgenic crops expressing Bacillus thuringiensis toxins. In the last years, resistance of S. frugiperda populations to transgenic corn was reported in different Latin American countries. The baculovirus Spodoptera frugiperda Multiple Nucleopolyhedrovirus (SfMNPV) is a pathogenic agent for the fall armyworm and a potential alternative for its control in integrated pest management strategies. In this work, we analyze some characteristics of two baculovirus isolates collected from maize (SfMNPV-M) and cotton (SfMNPV-C) fields from Argentina. The isolates were compared by restriction enzymes patterns and the analysis reveals the presence of genotypic variants in the SfMNPV-M isolate. We confirmed a deletion by sequencing fragments encompassing egt gene and most part of its contiguous gene (orf A) in a SfMNVP-M genotypic variant. Additionally, we estimated the 50% lethal dose and median survival time of each isolate in bioassays with S. frugiperda larvae.

中文翻译：

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贪食斜纹夜蛾多核多角体病毒阿根廷分离株的遗传变异。

秋天的夜蛾，Spodoptera frugiperda（JE Smith）是美洲的一种主要害虫。控制策略主要是通过使用化学杀虫剂和表达苏云金芽孢杆菌毒素的转基因作物来进行的。在过去的几年中，在不同的拉丁美洲国家中报道了弗氏链球菌对转基因玉米的抗性。杆状病毒贪食夜蛾多核多角体病毒（SfMNPV）是秋天粘虫的病原体，是其在病虫害综合防治策略中的潜在替代物。在这项工作中，我们分析了从阿根廷的玉米（SfMNPV-M）和棉花（SfMNPV-C）田中收集到的两种杆状病毒分离株的某些特征。通过限制酶图谱比较分离物，并且分析揭示了SfMNPV-M分离物中存在基因型变体。我们通过测序SfMNVP-M基因型变体中包含egt基因及其大部分连续基因（orf A）的片段来确认缺失。此外，我们估计了在用链球菌幼虫进行的生物测定中每种分离株的50％致死剂量和中位生存时间。