Screening of environmental fungi from Crete reveals candidates for biological control of mosquitoes

Mosquito-borne diseases remain a pressing global health concern, exacerbated by vector range-expansion and insecticide resistance. Entomopathogenic fungi represent a promising alternative to chemical insecticides, yet most mycoinsecticides are based on a few well-studied species. In this study, we surveyed environmental samples from Crete, Greece, isolating 46 isolates representing 13 genera. After a preliminary screening, 8 isolates were selected for larvicidal and adulticidal assays against Culex pipiens molestus Forskål (Diptera: Culicidae). The most promising isolate was BS2-C3 (Metarhizium Sorokin) which achieved over 90% mortality in both assays. Isolates from other genera (eg Cladosporium Link, Penicillium Link, Purpureocillium Luangsa-ard, Hywel-Jones, Houbraken & Samson) also exhibited activity, warranting further investigation. The performance of BS2-C3 was compared with commercially available strains GHA [Beauveria bassiana (Bals.-Criv.) Vuill.] and V275 (Metarhizium brunneum Petch), being as efficient as V275 and more efficient than GHA. These findings demonstrate that, in addition to the well-established genera, other fungal taxa may also harbor mosquitocidal potential, underscoring the importance of continued exploration of fungal diversity for biocontrol. Overall, our results expand the pool of fungi with demonstrated mosquito activity and highlight BS2-C3 (Metarhizium sp.) as a strong candidate for further development into safe, effective, and environmentally sustainable mycoinsecticides for integrated vector management.