Screening of Entomopathogenic Fungal Culture Extracts with Honeybee Nosemosis Inhibitory Activity.

This study aimed to select the most effective culture extracts for controlling honeybee nosemosis using 342 entomopathogenic fungi of 24 species from 18 genera. The germination inhibitory activity of the fungal culture extract on spores was evaluated using an in vitro germination assay method. Among 89 fungal culture extracts showing germination inhibitory activity of approximately 80% or more, 44 fungal culture extracts that maintained their inhibitory activity even at a concentration of 1% were selected. Finally, the honeybee nosemosis inhibitory activity was evaluated using the cultured extracts of five fungal isolates having a inhibitory activity of approximately 60% or more, even when the extract was removed after treatment. As a result, the proliferation of spores was reduced by all fungal culture extract treatments. However, only the treatment of the culture extracts from 364 and 60 showed a reduction in honeybee mortality due to nosemosis. In particular, the extracts of these two fungal isolates also increased the survival of honeybees.