The pathogenicity of 19 hypocrealean entomopathogenic fungi from seven different genera in adult Aedes aegypti was tested. All fungi proved to be pathogenic, and Isaria fumosorosea, Lecanicillium muscarium, Lecanicillium psalliotae, Metarhizium anisopliae, Metarhizium lepidiotae, Metarhizium majus, Metarhizium frigidum, Paecilomyces carneus, and Paecilomyces lilacinus caused total mortality within 15 days of exposure of mosquitoes to the fungal culture. All fungi developed on dead individuals. The high susceptibility of adults to most tested strains underlines the interest of entomopathogenic fungi-especially those of the genera Metarhizium, Isaria, Paecilomyces and Lecanicillium--for biological control of A. aegypti.

Significance and Impact of the Study: The entomopathogenic fungus Metarhizium anisopliae has been extensively studied as a potential agent for biological mosquito control. This study demonstrates the potential of M. anisopliae s.l. strain IP 46, which can infect adults, larvae and eggs of Aedes aegypti, against the eggs of this important vector species by indirect applications of oil-based conidial formulations. AbstractIncreasing needs for innovative control tools against the dengue vector Aedes aegypti have prompted investigations into the development of specific mycoinsecticides. The entomopathogenic fungus Metarhizium anisopliae attacks both larval and adult stages, but its ovicidal activity against A. aegypti is still little explored. This study reports important findings about the effectiveness of conidia formulated in water and oil-in-water emulsions and of direct and indirect application techniques against A. aegypti eggs. The ovicidal activity of M. anisopliae increased with higher conidial concentrations regardless of the application technique, and larvae elimination concentrations were lowest with oil-in-water-formulated conidia (LEC 50 ≤ 4Á8 9 10 3 conidia cm À2 and LEC 90 ≤ 1Á9 9 10 5 conidia cm À2 , respectively). Conidia eventually stimulated larval eclosion. Consequently, the indirect application of oil-based fungal formulations onto substrates where oviposition will later occur appears to be a more efficient means to infect those eggs than the direct fungal application to previously deposited eggs.

ARSEF 1580, in the group of tested isolates, is the most promising isolate for use against terrestrial eggs, aquatic larvae and adults of this important vector.

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