European corn borer (Ostrinia nubilalis) is an important maize pest which is treated mainly by synthetic pesticides with many negative effects for ecosystem and human health. Soil borne entomopathogenic fungi of species belonging to Beauveria genus may provide an alternative strategy for biological control of this pest. In this article, we report results of virulence testing of 46 soil isolates of Beauveria spp. against O. nubilalis in relation to isolates origin and haplotype. All strains were collected from soil using Galleria mellonella bait method. Conidia suspension with concentration 107 conidia in ml was used for virulence test against 4th instar larvae of O. nubilalis at temperature 25°C. After 14 days, mortality of larvae was in the range 34%–96%. Median lethal time LT50 was estimated to 5.5–21.3 days. Mortality was not in relation to habitat or any other environmental parameter of sites where isolates came from. Differences among species were insignificant. Isolates were divided into 8 genetic lineages and 14 haplotypes using sequencing of ITS and Bloc nuclear regions. None of the lineages showed higher mortality than others. Despite more or less virulent isolates being found in each lineage, the three most virulent isolates belonged to the same lineage Beauveria bassiana A3. The four most virulent isolates were compared to commercial isolate GHA to assess medium lethal concentration. LC50 were estimated in range 7.5 × 104 to 9.5 × 105. Three of the four isolates showed equal or greater efficiency than strain GHA.

中文翻译：

---

白僵菌毒力的变异性。抗 Ostrinia nubilalis 的土壤分离物

欧洲玉米螟（Ostrinia nubilalis）是一种重要的玉米害虫，主要采用合成农药防治，对生态系统和人类健康有许多负面影响。白僵菌属物种的土壤传播昆虫病原真菌可能为这种害虫的生物防治提供替代策略。在本文中，我们报告了白僵菌属 46 个土壤分离株的毒力测试结果。针对 O. nubilalis 与分离株起源和单倍型有关。使用大蜡螟诱饵法从土壤中收集所有菌株。分生孢子浓度为107ml的分生孢子悬浮液在25℃温度下对O. nubilalis 4龄幼虫进行毒力试验。14 天后，幼虫的死亡率在 34%–96% 之间。中位致死时间 LT50 估计为 5.5-21.3 天。死亡率与栖息地或分离株来源地的任何其他环境参数无关。物种之间的差异是微不足道的。使用 ITS 和 Bloc 核区域的测序将分离物分为 8 个遗传谱系和 14 个单倍型。没有一个谱系显示出比其他谱系更高的死亡率。尽管在每个谱系中都发现了或多或少的毒力分离株，但三个毒性最强的分离株属于同一谱系白僵菌 A3。将四种毒性最强的分离株与商业分离株 GHA 进行比较，以评估中等致死浓度。LC50 估计在 7.5 × 104 到 9.5 × 105 的范围内。四种分离物中的三种表现出与 GHA 菌株相同或更高的效率。使用 ITS 和 Bloc 核区域的测序将分离物分为 8 个遗传谱系和 14 个单倍型。没有一个谱系显示出比其他谱系更高的死亡率。尽管在每个谱系中都发现了或多或少的毒力分离株，但三个毒性最强的分离株属于同一谱系白僵菌 A3。将四种毒性最强的分离株与商业分离株 GHA 进行比较，以评估中等致死浓度。LC50 估计在 7.5 × 104 到 9.5 × 105 的范围内。四种分离物中的三种表现出与 GHA 菌株相同或更高的效率。使用 ITS 和 Bloc 核区域的测序将分离物分为 8 个遗传谱系和 14 个单倍型。没有一个谱系显示出比其他谱系更高的死亡率。尽管在每个谱系中都发现了或多或少的毒力分离株，但三个毒性最强的分离株属于同一谱系白僵菌 A3。将四种毒性最强的分离株与商业分离株 GHA 进行比较，以评估中等致死浓度。LC50 估计在 7.5 × 104 到 9.5 × 105 的范围内。四种分离物中的三种表现出与 GHA 菌株相同或更高的效率。三个毒性最强的分离株属于同一谱系白僵菌 A3。将四种毒性最强的分离株与商业分离株 GHA 进行比较，以评估中等致死浓度。LC50 估计在 7.5 × 104 到 9.5 × 105 的范围内。四种分离物中的三种表现出与 GHA 菌株相同或更高的效率。三个最毒力的分离株属于同一谱系白僵菌 A3。将四种毒性最强的分离株与商业分离株 GHA 进行比较，以评估中等致死浓度。LC50 估计在 7.5 × 104 到 9.5 × 105 的范围内。四种分离物中的三种表现出与 GHA 菌株相同或更高的效率。