Evaluation of the pathogenicity and infectivity of entomopathogenic hypocrealean fungi, isolated from wild mosquitoes in Japan and Burkina Faso, against female adult Anopheles stephensi mosquitoes

• Mosquitoes were naturally infected with various entomopathogenic hypocrealean fungi.
• The fungal diversity in Japan was higher than that in Burkina Faso.
• Seven isolates of entomopathogenic fungi exhibited high pathogenicity to mosquitoes.
• Seven isolates of Beauveria spp. killed >90 % of mosquitoes within two weeks.

We investigated the potential of entomopathogenic hypocrealean fungi that naturally occur in or on adult mosquitoes for use as biocontrol agents of vector mosquitoes. The fungi were isolated from wild mosquitoes collected in Japan and Burkina Faso using two isolation methods (with and without surface sterilization). Detected fungal species included Beauveria bassiana sensu lato, Isaria spp., Paecilomyces spp., Lecanicillium spp., and Simplicillium spp. These isolates were used in bioassays against adult female Anopheles stephensi mosquitoes. The median survival time ranged from 5.8 to 14.9 d (control, 17.0 d). Reduced survival times were observed in the isolates from surface-sterilized mosquitoes from Japan, with the isolate B. bassiana s.l. 60-2 exhibiting the highest virulence. This study indicates that adult mosquitoes are naturally infected with various entomopathogenic hypocrealean fungi, and that some of these isolates have the potential for use as fungal pesticides to control vector mosquitoes.