Screening of the Entomopathogenic Fungi, Metarhizium anisopliae and Beauveri bassiana against Early Larval Instars of Anopheles stephensi (Diptera: Culicidae)

摘要

Despite many prevention and control programs, the disease of malaria still remains a major health and economic problem in developing countries due to the unexpected resistance of malaria mosquitoes to chemical insecticides. In this study, the virulence of 10 Iranian isolates of the entomopathogenous fungi Beauveria bassiana and Metarhizium anisoplaie were evaluated against Anopheles stephensi larvae. Different strains were screened by adding aqueous suspension of 108 conidia mL-1 to 100 mL water containing 25 early instars larvae. The results showed that Bb 429C and Bb 796C were the most virulent isolates of B. bassiana causing 100% larval mortality with lethal times of 2.29 and 2.53 days for LT50 and 4.34 and 4.34 days for LT90, respectively. Among M. anisopliae isolates, Ma 1018C was the most efficient isolate. Larval mortality rates caused by Ma 1018C at concentrations of 5x107, 108 and 5x108 conidia mL-1 were not significantly different as respectively they killed 99, 97 and 99% of larva at the fourth day. The lowest lethal times were related to the concentration of 5x107conidia mL-1 and were 0.63 and 1.93 days for LT50 and LT90, respectively. Entomopathogenic fungi could be promising prospects and safe alternatives in integrated mosquitoes control programs.