Isolation and characterization of a high-efficacy Beauveria bassiana strain from the European tent caterpillar, Malacosoma neustria Linnaeus (Lepidoptera: Lasiocampidae).

The European tent caterpillar, Malacosoma neustria Linnaeus (Lepidoptera: Lasiocampidae), is a worldwide known pest that causes significant losses by feeding on many woody and shrub-like plants during the larval period. In this study, a Beauveria bassiana strain isolated from M. neustria larvae and characterized according to its morphological and molecular properties. Its insecticidal activity was tested on M. neustria larvae. Sequence results of partial ITS (ITS1-5.8S-ITS2) gene region identified the isolate (named as Mn1) as a B. bassiana strain. Phylogenetic analysis showed that Mn1 strain displays close similarity to B. bassiana ARSEF 1848 and ARSEF 751 isolates. According to the concentration-responce tests performed using 1 × 10 ³  - 1 × 10 ⁹ conidia per mL concentrations, LC ₅₀ value of the new strain was calculated as 1 × 10 ⁵ conidia per mL within 7 days against the larvae of M. neustria in the laboratory conditions. B. bassiana Mn1 strain, characterized in this study, is recorded as the first entomopathogenic fungus isolated from M. neustria, and the results showed that new strain of B. bassiana has a serious potential to be utilized as a good biocontrol agent against M. neustria.
(© 2023. Institute of Microbiology, Academy of Sciences of the Czech Republic, v.v.i.)