Non-target phyllophagous insects in oak forests of central and southeastern Europe as potential hosts of Entomophaga maimaiga

Abstract: Entomophaga maimaiga is an important host-specific fungal pathogen of gypsy moth larvae in North America. In 1999, this entomopathogenic fungus was successfully introduced into Bulgaria. At present, it is spreading fast in southeastern and central Europe. It has been recorded from Serbia, Greece, Macedonia, Romania, Hungary, Slovakia, and the Czech Republic. European oak forests harbour a very rich and diverse entomofauna, which consists of many uncommon, rare, and protected species. E. maimaiga thus might pose a threat to such insect species. In this study, we evaluated the presence of entomopathogens in non-target phyllophagous larvae in Slovakia (two plots), Hungary (three plots), and Bulgaria (one plot). The surveys were conducted in areas where E. maimaiga had previously been reported and as many as 4045 larvae were collected. In total, 45 (1.13%) collected larvae died because of fungal infections but none of them was infected by E. maimaiga. Pathogens were identified as Beauveria bassiana, B. pseudobassiana, Zoophthora radicans, Aspergillus flavus, and an unidentified species from the family Entomophthoraceae. Mean prevalence of E. maimaiga infection in collected gypsy moth larvae reached 0.84% at the surveyed plots. Our results confirm a high host specificity of E. maimaiga to Lymantria dispar.