Pathogenicity assessment of entomopathogenic fungi infecting Leptoglossus occidentalis (Heteroptera: Coreidae)

Leptoglossus occidentalis, an insect species native to North America, is a pest of conifer seed orchards in its natural distribution area. Recently, it was accidentally introduced into Europe where its populations have been expanding throughout the continent. In this study we evaluated the pathogenicity of Beauveria bassiana, Isaria fumosorosea, and Metarhizium anisopliae to this pest under laboratory and outdoor conditions. Pathogenicity varied depending upon isolates, exposure methods and location of bioassay. In the laboratory, LC50 values were highest for I. fumosorosea and lowest for M. anisopliae, and an indirect exposure was less effective than a direct one. In outdoor experiments the overall mortality was in all isolates significantly lower than mortality in the laboratory, and inter-specific variability in pathogenicity was not as prominent outdoors as in the laboratory. The results of this bioassay showed that I. fumosorosea has the potential as a microbial control agent of L. occidentalis.