Efficacy and molecular studies of a Lebanese isolate of Beauveria for control of Thaumetopoea wilkinsoni (Lepidoptera: Thaumetopoeidae)

Abstract

A Lebanese isolate of a Beauveria species originally isolated from a hymenopterous insect pest was found to be very effective against the pine processionary moth Thaumetopoea wilkinsoni. In laboratory bioassays, high mortality rates of the five larval stages were attained with spore concentrations of about 5000–50,000 spores/larva. The efficacy of kill on the first three larval stages was similar to the growth regulator diflubenzuron, but it was significantly higher on the fourth and fifth larval stages. Sequences of the DNA lyase gene and the EF-1α gene were used for molecular characterisation of this Beauveria isolate. The DNA lyase gene showed more polymorphism than the previously reported ITS region and EF-1α gene. This constitutes the first report on the possibility of using the DNA lyase gene as a molecular tool in fungal taxonomy.

Keywords:

• Beauveria
• Thaumetopoea wilkinsoni
• pine processionary moth
• DNA lyase gene

Acknowledgements

Cultures of strains of Beauveria for molecular analysis were obtained from the USDA-ARS Collection of Entomopathogenic Fungal Cultures (ARSEF, Ithaca, NY); with thanks to Dr Richard A. Humber, curator, and Karen S. Hansen, Biological Technician. This work was partially funded by the Lebanese National Council for Scientific Research and by a grant to the Lebanese Ministry of Environment from the Global Environment Facility and the United Nations Environment Program and implemented by the American University of Beirut for the project ‘Integrated Management of Cedar Forests in Lebanon in Cooperation with other Mediterranean Countries’. The technical assistance of Ms Hana Sobh is appreciated.