Diversity and prevalence of entomopathogenic fungi (Ascomycota, Hypocreales) in epidemic populations of bark beetles (Coleoptera, Scolytinae) in spruce forests of the Tatra National Park in Slovakia

Bark beetles are serious pests for forestry in Slovakia. Their outbreaks may have significant ecological and economic impacts on spruce forests. Effective control of bark beetles is difficult due to their cryptic habits, however, microbial control using entomopathogenic fungi is believed to be a promising alternative to traditional control measures. During 2014–2015, diversity and prevalence of entomopathogenic fungi was studied in populations of bark beetles infesting spruce forests affected by windstorms in the Tatra National Park in Slovakia. Three Beauveria species, B. bassiana , B. caledonica and B. pseudobassiana , together with Metapochonia bulbillosa were identified from 271 specimens of three bark beetle species, Ips typographus , Ips amitinus and Pityogenes chalcographus . Beauveria bassiana was the predominant pathogen and infected all three bark beetle species. Phylogenetic analysis identified three phylogenetic groups of B. bassiana in the evaluated host populations. M. bulbillosa was reported for the first time from bark beetle hosts and Slovakia. The prevalence of fungal infection in natural populations of I. typographus was low and varied between 0.07 and 0.72%.