Discovery of novel entomopathogenic fungi for mosquito borne disease control

The increased application of chemical control programmes has led to the emergence and spread of insecticide resistance in mosquitoes. Substitutive, effective and environmentally safe control strategies are currently needed for the control of disease vector mosquitoes. The use of entomopathogenic fungi could be a suitable alternative to chemical insecticides. Currently, Beauveria sp. and Metharizium are the most widely used entomopathogenic fungi for mosquito control but increasing the arsenal with additional fungi is needed to mitigate the emergence of resistance. Entomopathogenic fungi are distributed in a wide range of mosquito-endemic habitats. We have performed a comprehensive screen for candidate mosquitocidal fungi from diverse environments, resulting in the isolation of ten fungi from Maryland and 26 from Puerto Rico.
An initial screening involving adult An. gambiae and Ae. aegypti exposure to two weeks old-fungal cultures identified five potent pathogenic fungi belonging to the genera Mucor, Galactomyces, Isaria, Aspergillus and Aaosphaeria. The entomopathogenic effects of these fungi were also confirmed through conidial solution exposure assays. We also probe into the killing mechanisms of these fungi and investigate whether the mosquitocidal activities could be a result of potential toxic fungus-produced metabolites, or the actual infection by live fungi. Preliminary assays involving the exposure of mosquitoes to sterile filtered culture supernatants show that Isaria and Galactomyces are the strongest producers of lethal metabolites against mosquitoes.
Further investigations through the characterization of those entomopathogenic fungi and their metabolites need to be done to confirm their potential use in biologic control against mosquitoes