Identification of Entomopathogenic Fungi as Naturally Occurring Enemies of the Invasive Oak Lace Bug, Corythucha arcuata (Say) (Hemiptera: Tingidae)

SIMPLE SUMMARY: The oak lace bug (OLB), Corythucha arcuata, is a cell sap-sucking insect that is native to North America but has spread rapidly in European countries as an invasive pest. The main hosts are oaks, but it can develop on other forest species as well. Its occurrence is worrying in terms of the cumulative impacts that it could have on forests, as well as the molestation of imago in cities that have been frequently reported. Since the pest is still a new element of a biocoenosis, there is a lack of research on its natural enemies and competitors that could form a potential foundation for biological control strategies. Although there have been reports that lace bugs are quite susceptible to a fungal diseases amid more humid conditions, to date, none of the pathogenic fungi found on OLBs under natural conditions were identified in the literature. In this study, we provide evidence of four entomopathogenic fungi: Beauveria pseudobassiana, Lecanicillium pissodis, Akanthomyces attenuatus and Samsoniella alboaurantium that could present a potential as biological control agents against OLBs. ABSTRACT: The oak lace bug (OLB), Corythucha arcuata (Hemiptera: Tingidae), was first identified as an invasive pest in Europe in northern Italy in 2000 and since then it has spread rapidly, attacking large forested areas in European countries. The OLB is a cell sap-sucking insect that is native to North America, with Quercus spp. as its main host. Its rapid expansion, successful establishment in invaded countries, and observations of more damage to hosts compared to native areas are most likely due to a lack of natural enemies, pathogens and competitors. In its native area, various natural enemies of OLBs have been identified; however, little is known about the occurrence and impact of OLB pathogens. None of the pathogenic fungi found on OLBs in natural conditions have been identified until now. In this study, we provide evidence of four entomopathogenic fungi that are naturally occurring on invasive OLBs found in infested pedunculate oak forests in eastern Croatia. On the basis of their morphology and multilocus molecular phylogeny, the fungi were identified as Beauveria pseudobassiana, Lecanicillium pissodis, Akanthomyces attenuatus and Samsoniella alboaurantium. The sequences generated for this study are available from GenBank under the accession numbers MT004817-MT004820, MT004833-MT004835, MT027501-MT27510, and MT001936-MT0011943. These pathogenic species could facilitate biological control strategies against OLBs.