Department of Entomology and Wildlife Ecology, University of Delaware, Newark, Delaware, USA.
DuPont-Pioneer, Wilmington, Delaware, USA.
Pest Manag Sci. 2021 Sep;77(9):4091-4099. doi: 10.1002/ps.6434. Epub 2021 May 13.
The fall armyworm, Spodoptera frugiperda (Smith), is a pest of many economically essential crops across several continents. Documentation of resistance to Bt toxins has caused growing concern in agricultural communities regarding the ability to keep fall armyworm populations below economic thresholds. The existence of two host strains referred to as the 'rice' and 'corn' strains is a complicating and under-researched factor of fall armyworm biology and management. It is essential to characterize the differences between the host strains, as well as their rice/corn hybrid offspring, to elucidate their contributions to field-evolved resistance.
Corn was a preferred oviposition host for both rice and corn strain fall armyworm, and a suitable larval host plant for each of the four populations tested. Corn strain females displayed a significant preference towards oviposition on plants that lacked mechanical damage. The rice strain population was generally less tolerant to Cry1F corn tissue than the corn strain and hybrid populations, which performed in a similar way to one another.
The preference for corn as an ovipositional host may have an impact on resistance management when coupled with differential host strain Bt tolerances, though more studies are needed. Hybrid tolerance to Bt toxins could possibly contribute to the evolution of Bt resistance. This is the first study to compare the larval fitness and survival of rice/corn hybrid fall armyworm to that of pure host strains using a tissue-based approach.
秋黏虫（Spodoptera frugiperda（Smith））是一种害虫，危害着多个大陆上的许多经济作物。Bt 毒素抗性的记录引起了农业社区对控制秋黏虫种群数量低于经济阈值能力的日益关注。存在两种被称为“水稻”和“玉米”株系的宿主株系是秋黏虫生物学和管理中一个复杂且研究不足的因素。对宿主株系及其水稻/玉米杂交后代之间的差异进行特征描述，对于阐明它们对田间进化抗性的贡献至关重要。
玉米是水稻和玉米株系秋黏虫都喜欢产卵的宿主，也是四种供试种群的合适幼虫寄主植物。玉米株系的雌性对缺乏机械损伤的植物表现出明显的产卵偏好。与玉米株系和杂交种群相比，水稻株系种群对 Cry1F 玉米组织的耐受性一般较差，而后者表现相似。
当与不同的宿主株系 Bt 耐受性相结合时，将玉米作为产卵宿主的偏好可能会对抗性管理产生影响，尽管还需要更多的研究。Bt 毒素的杂种耐受性可能有助于 Bt 抗性的进化。这是首次使用基于组织的方法比较水稻/玉米杂交秋黏虫与纯宿主株系的幼虫适应性和存活率的研究。
