背景:小菜蛾(DBM)(小菜蛾)对全球作物生产造成了巨大损失。常规杀虫剂由于抗性而失去效力。因此,在病虫害综合治理中,对昆虫病原真菌(EPF)等可持续控制方法的兴趣越来越大。然而,真菌的田间功效因环境影响而变化。在这项研究中,一组来自不同位置的50个白僵菌菌株的特征在于其分生孢子产生的基因型和表型,温度和UV-B辐射耐受性,和对DBM的毒力。
结果:系统发育分析揭示了两种不同的物种:球孢白僵菌(84%)和假球芽孢杆菌(16%)。大多数菌株在25°C至28°C之间表现出最佳生长,在10°C和33°C下严重影响发芽。值得注意的是,44%的人对UV-B辐射(5.94kJm-2)具有很高的抵抗力,发芽率在60.9%至88.1%之间。地理来源与温度或紫外线辐射耐受性没有相关性。在毒力实验中,在暴露于4mL分生孢子悬浮液(107分生孢子/mL)后7天,在DBM第二龄幼虫中,有52%的菌株导致死亡率超过80%。
结论:环境条件下的生存对于基于EPF的商业产品对抗DBM至关重要。结果表明,与地理起源相比,对环境应激源的应变耐受性更多地与特定的微气候因素有关。每个菌株都表现出独特的特征;例如,毒力最强的菌株(#29)对紫外线高度敏感。因此,表征不同的菌株提供了必要的基因型和表型见解,这对于理解它们作为生物控制剂的作用,同时促进有效的生物农药产品开发和吸收至关重要。©2024作者(S)。害虫管理科学由JohnWiley&SonsLtd代表化学工业学会出版。
BACKGROUND: The diamondback moth (DBM) (Plutella xylostella) causes large losses to global crop production. Conventional insecticides are losing effectiveness due to resistance. Consequently, there is a growing interest in sustainable control methods like entomopathogenic fungi (EPF) in Integrated Pest Management. However, the field efficacy of fungi varies due to environmental influences. In this study, a group of 50 Beauveria strains sourced from different locations were characterized by genotype and phenotype with respect to their conidial production, temperature and UV-B radiation tolerance, and virulence against DBM.
RESULTS: Phylogenetic analysis revealed two distinct species: Beauveria bassiana (84%) and B. pseudobassiana (16%). Most strains showed optimal growth between 25 °C and 28 °C, with germination severely affected at 10 °C and 33 °C. Notably, 44% displayed high resistance to UV-B radiation (5.94 kJ m-2), with germination rates between 60.9% and 88.1%. Geographical origin showed no correlation with temperature or UV radiation tolerance. In virulence experiments, 52% of strains caused mortality rates exceeding 80% in DBM second instars at 7 days after exposure to a 4 mL conidial suspension (107 conidia/mL).
CONCLUSIONS: Survival under environmental conditions is crucial for EPF-based commercial products against DBM. Results suggest strain tolerance to environmental stressors is more tied to specific micro-climatic factors than geographical origin. Each strain exhibited unique characteristics; for example, the most virulent strain (#29) was highly UV-sensitive. Therefore, characterizing diverse strains provides essential genotypic and phenotypic insights, which are fundamental for understanding their role as biocontrol agents while facilitating efficient
biopesticide product development and uptake. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.