Lethal effects of Gliocladium virens, Beauveria bassiana and Metarhizium anisopliae on the malaria vector Anopheles albimanus (Diptera: Culicidae)

Abstract

Control of Anopheles albimanus, the main vector of malaria on the coast of the State of Chiapas, is based mainly on application of chemical insecticides, which has resulted in resistance to most registered insecticides. Strategies for biological control may provide sustainable alternatives. We report on the lethal effects of a native isolate of Gliocladium virens on An. albimanus larvae and adults, compared to that of strains of Beauveria bassiana and Metarhizium anisopliae. Conidial suspensions of G. virens, B. bassiana and M. anisopliae cultured on Sabouraud agar were tested in bioassays with An. albimanus larvae and adults. Mosquito larvae were more susceptible to all fungi, compared to adults. On early and late instar larvae, M. anisopliae showed the most pathogenic effect (LC₅₀ of 1.4×10⁵ conidia/mL in early instars; 1.1×10⁵ conidia/mL in late instars), followed by G. virens (LC₅₀ of 3.3×10⁵ conidia/mL in early instars and 3.5×10⁶ conidia/mL in late instars). Metarhizium anisopliae sensu lato and the native G. virens could be considered good choices for An. albimanus control in southern Mexico.

Keywords:

• Anopheles albimanus
• entomopathogenic fungi
• mosquitoes
• biological control

Acknowledgements

We thank Jorge E. Ibarra Rendón, CINVESTAV-Irapuato for his donation of Metarhizium anisopliae and Beauveria bassiana isolates; Olga R. Gálvez Coutiño and Octavia Perez Medina for their technical help; the National Council of Science and Technology, who financed this study through Project FOSISS No. 13972.