Biological control of Asian tiger mosquito, Aedes albopictus (Diptera: Culicidae) using Metarhizium anisopliae JEF-003 millet grain

Mosquitoes have been becoming serious vectors worldwide thus effective and safe control strategies should be established. Entomopathogenic fungi can be alternative controlling agents by substituting chemical insecticides. Herein we assayed 12 soil-borne entomopathogenic fungi against Asian tiger mosquito (Aedes albopictus) larvae in laboratory conditions and tried to establish an effective application method using millet granular formulation (GR). Twelve fungal isolates which belong to 6 genera (Beauveria, Cordyceps, Metarhizium, Paecilomyces, Purpureocillium and Verticillium) were assayed; M. anisopliae JEF-003 showed the fastest mosquitocidal activity, approximately 73% mortality rate at 2days post-inoculation (dpi.) and >90% mortality rate at 5dpi. Conidia of M. anisopliae JEF-003 also showed a dosage dependent activity at 1×10⁵, 1×10⁶ and 1×10⁷conidiaml^-1. Hyphal growth of M. anisopliae JEF-003 in the Ae. albopictus larvae was observed by infection of an M. anisopliae JEF-003 EGFP-transformant, which was generated by restriction enzyme-mediated integration (REMI) method. GR of M. anisopliae JEF-003 showed high virulence to Ae. albopictus larvae (>90% mortality) after 5days of application. These results suggest that M. anisopliae JEF-003 has a potential to control A. albopictus larvae and GR can be practically used for management of the serious vector in water environment.