Epizootiology of infections by Batkoa major (Entomophthorales: Batkoaceae) and Beauveria bassiana (Hypocreales: Cordycipitaceae) in spotted lanternfly (Hemiptera: Fulgoridae) populations

Abstract

The planthopper Lycorma delicatula (White) (spotted lanternfly; SLF) was introduced to North America from Asia. It was first found in southeastern Pennsylvania in 2014 and now, a decade later, has increased in abundance and spread into 18 eastern US states. To study naturally occurring fungal pathogens infecting SLF, eastern Pennsylvania sites were sampled every 1 to 2 wk in 2020 and 2021 during the adult life stage of L. delicatula to detect prevalence of infections by the fungi Batkoa major (Thaxt.) Humber (Entomophthorales: Batkoaceae) and Beauveria bassiana (Bals.-Criv.) Vuill. (Hypocreales: Cordycipitaceae). To sample, living adult SLF were collected and reared and cause of death was diagnosed. In 2020, at the site hosting a co-epizootic of these 2 generalist pathogens in 2018, an epizootic caused by B. major was documented from 30 September to 21 October. Low levels of infection by both pathogens were detected at an additional 2020 site and both 2021 sites. Overall, there was a negative association of B. major infection with SLF density and no association with density for B. bassiana. Co-infections in individual SLF by both fungi were never documented, and there was an inverse relationship between prevalence of B. major and B. bassiana infections in the sampled populations. At the time that SLF for rearing were sampled, adult cadavers were also sampled. For B. major, infection rates of sampled cadavers and reared individuals were positively correlated, but higher infection rates were observed in cadavers than among reared SLF. For B. bassiana, no such pattern occurred.

Keywords: Lycorma delicatula; entomopathogenic fungi; epizootic; generalist pathogen; invasive species.