Beekeeping is one of the main economic activities in several countries, and Argentina has become one of the most important exporters of honey and other products from hives. Ascosferosis, an emerging disease caused by the fungus Ascosphaera apis, affects bee larvae, causing mortality in the colonies. While many studies have focused on the infections of European Apis mellifera bees, we studied hybrid Apis mellifera scutellata bees from northern Argentina and fungal strains isolated from commercial pollen from Spanish provinces, to determine the susceptibility of local bees to the entomopathogenic A. apis. Different groups of larvae were administered sugar syrup suspensions with ascospores at different concentrations: a lower concentration of 5 × 10³ spores/mL was used to know the susceptibility of the larvae and a higher concentration of 5 × 10⁶ spores/mL was used to determine the pathogenicity, resulting in an average infection of 30% of the mummified larvae. Besides, an intermediate concentration of 5 × 10⁴ spores/mL was administered, which allowed us to identify the most pathogenic strain at this concentration. This work provides the first approximation to the pathogenic effect of Spanish fungal strains on larvae of bees from northern Argentina.

养蜂业是几个国家的主要经济活动之一，阿根廷已成为蜂蜜和其他蜂箱产品最重要的出口国之一。Ascosferosis 是一种由Ascosphaera api真菌引起的新兴疾病，它会影响蜜蜂幼虫，导致蜂群死亡。虽然许多研究都集中在欧洲蜜蜂的感染上，但我们研究了来自阿根廷北部的杂交Apis mellifera scutellata蜜蜂和从西班牙各省的商业花粉中分离出的真菌菌株，以确定当地蜜蜂对昆虫病原性A. apis的易感性. 给不同组的幼虫施用不同浓度的子囊孢子糖浆悬浮液：使用较低浓度的 5 × 10 ³孢子/mL 了解幼虫的易感性，使用较高浓度的 5 × 10 ⁶孢子/mL 来了解幼虫的易感性。确定致病性，导致平均感染 30% 的木乃伊幼虫。此外，施用了5 × 10 ⁴孢子/mL的中间浓度，这使我们能够确定该浓度下最具致病性的菌株。这项工作首次估计了西班牙真菌菌株对阿根廷北部蜜蜂幼虫的致病作用。