Entomopathogenic nematodes (EPNs) have been regarded as the most convenient strategy for insect pest management. The native strains of EPNs: Heterorhabditis bacteriophora EUPT-SD, H. bacteriophora EUPT-R, H. bacteriophora EUPT-KN, H. bacteriophora EUPT-K and H. bacteriophora EUPT-H isolated from mid-Himalayan region of Himachal Pradesh were tested in laboratory for their multiplication and virulence against 3rd and 4th larval instars of the tobacco cutworm, Spodoptera litura Fabricius (Lepidoptera: Noctuidae), the serious polyphagous pest affecting a wide range of agricultural crops worldwide. All the EPN strains were effective against 3rd and 4th larval instars of S. litura. Insect mortality reached 90–96% after 96 h at nematode concentrations of 150 infective juveniles (IJs)/ml. The insect mortality was also recorded at low concentrations of IJs, but the most exposure period was required. High virulence was shown by H. bacteriophora EUPT-SD 96 and 94%, followed by H. bacteriophora EUPT-R 92 and 90%, H. bacteriophora EUPT-KN 92 and 90%, H. bacteriophora EUPT-K 92 and 90% and H. bacteriophora EUPT-H 92 and 90%, respectively, against 3rd and 4th larval instars in terms of reproductive potential and killing. All the insects were alive in the absolute control. Utilization of EPNs for the management of S. litura may be the best method to overcome the insect resistance problems and to manage the population of this insect pest. It may be an effective method and may be a partial substitute of synthetic insecticides, thus minimizing the excessive use of synthetic chemicals. The results demonstrated the potential of indigenous EPNs isolates against S. litura, but before further recommendation, multiplication field trials need to be conducted to confirm their efficacy at farm level.

中文翻译：

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昆虫病原线虫 (EPN) 本土分离株对烟草地老虎、斜纹夜蛾 (鳞翅目：夜蛾科) 的杀生物潜力

昆虫病原线虫（EPNs）被认为是最方便的害虫管理策略。测试了从喜马偕尔邦中部喜马拉雅地区分离的 EPNs 的天然菌株：Heterorhabditis bacteriophora EUPT-SD、H. bacteriophora EUPT-R、H. bacteriophora EUPT-KN、H. bacteriophora EUPT-K 和 H. bacteriophora EUPT-H在实验室中，它们对烟草地老虎、斜纹夜蛾（鳞翅目：夜蛾科）的第 3 和第 4 幼虫龄期的繁殖和毒力，这是一种严重的多食性害虫，影响全球范围内的多种农作物。所有EPN菌株均对斜纹夜蛾3龄和4龄幼虫有效。线虫浓度为 150 只感染幼虫 (IJs)/ml 时，昆虫死亡率在 96 小时后达到 90-96%。在低浓度的 IJ 下也记录了昆虫死亡率，但需要最长的暴露时间。H. bacteriophora EUPT-SD 96 和 94% 显示出高毒力，其次是 H. bacteriophora EUPT-R 92 和 90%、H. bacteriophora EUPT-KN 92 和 90%、H. bacteriophora EUPT-K 92 和 90%和 H. bacteriophora EUPT-H 92 和 90%，分别针对繁殖潜力和杀伤力的第 3 和第 4 幼虫龄。在绝对控制下所有的昆虫都是活的。利用 EPN 管理斜纹夜蛾可能是克服昆虫抗性问题和管理这种害虫种群的最佳方法。它可能是一种有效的方法，可能是合成杀虫剂的部分替代品，从而最大限度地减少合成化学品的过度使用。结果证明了本土 EPNs 分离株对斜纹夜蛾的潜力，但在进一步推荐之前，