Pathogenicity of native isolates of entomopathogenic fungi Beauveria and Metharizium genera on Microcerotermes diversus (Blattodea: Termitidae) in the laboratory

Abstract

Microcerotermes diversus Silvestri (Blattodea: Termitidae) is a worldwide destructive termite whose control by conventional methods is often difficult. Biological control using entomopathogenic fungi could be an alternative management strategy. Two species of entomopathogenic fungi, Metarhizium anisopliae and Beauveria bassiana, isolated from natural habitats of Mashhad and Lahijan regions, Iran. The fungi were characterized based on sequences of ITS gene as well as classic data. Then, the infectivity of both isolates of M. anisopliae and B. bassiana in different concentrations (1 × 104, 1 × 105, 1 × 106, 1 × 107, and 1 × 108 conidia/ml) were evaluated under laboratory conditions by two methods, including spray and pipetting against termite, M. diversus. Both entomopathogenic fungi species were capable of infecting and killing M. divesrus. In the pipetting method, the LC50 value for B. bassiana and M. anisopliae calculated 8.03 × 105 (conidia/ml) and 1.03 × 106 (conidia/ml), respectively. But in the spray method, the effect of M. anisopliae on M. diversus was more than B. bassiana. The LC50 value in the spray method for B. bassiana and M. anisopliae was 3.52 × 107 (conidia/ml) and 1.65 × 106 (conidia/ml). The mortality caused by the fungus was dose-dependent, with the highest mortality recorded at the highest concentration. In the pipetting method, the mortality rate for B. bassiana and M. anisopliae was 0 to 97.5% and 0 to 100% at 8 day post infection. In the spray method, the mortality percentage for B. bassiana was from 2.5 to 72.5% and for M. anisopliae was 0 to100% by 4 days post-infection. The results of this study indicated that B. bassiana and M. anisopliae are potentially useful biological control agents for M. diversus. Future studies with field trails will provide a confident approach toward termite management.