Entomopathogenic fungi for control of spotted lanternflies

A total of 19 species of entomopathogenic fungi have been recorded infecting spotted lanternflies, Lycorma delicatula (SLF), in nature in the northeast. While infections by most species are at low levels, Batkoa major and Beauveria bassiana have caused epizootics although only B. bassiana infections are evident every year. As B. bassiana conidia are not airborne, we assume that SLF naturally contact these conidia in the environment and therefore on the ventral sides of their bodies. To confirm, tree trunks were sprayed with B. bassiana (Bioceres) and then SLF adults were caged for 3 days over the sprayed areas. 92% of SLF from cages died of B. bassiana infections. We then asked whether the SLF forewings might provide a protective roof over the body and whether conidia cannot infect when applied dorsally, to the adult forewings, as might occur if spraying adult aggregations. Conidia in oil were topically applied to SLF adults on the ventral sides of their abdomens in comparison with applications to the forewings. Significantly more SLF inoculated with B. bassiana on their abdomens died from B. bassiana infections (57%) although 26% of those inoculated on the wings also became infected. Therefore, it appeared that while horizontal transmission perhaps usually occurs when conidia contact the ventral surfaces of SLFs, some infection can occur when conidia contact SLF forewings.