Evaluation of fabric bands for dissemination of the fungal pathogen Beauveria bassiana to the invasive spotted lanternfly ( Lycorma delicatula )

The spotted lanternfly (SLF) (Lycorma delicatula) (White) is an invasive insect pest that was introduced to the United States over a decade ago and has since caused severe economic damages to forestry, ornamental plant, and viticulture industries. The fungal entomopathogen Beauveria bassiana is a promising biological control agent that can infect and kill nymphal and adult SLF. However, spray applications in the field have yielded mixed results, potentially due to low residual efficacy, movement of SLF out of treated areas, or inadequate levels of direct coverage on insects. Here, we tested the efficacy of pieces of fabric soaked in a B. bassiana spore suspension (‘fungal bands’), which can be attached to tree trunks and passively disseminate the pathogen to insects that walk across it. In laboratory bioassays, fungal bands (soaked in 1 × 109 spores/mL solution) killed over 60% of nymphs five days after exposure. Ninety-four per cent of all treated nymphs were confirmed to be infected with B. bassiana. Under field conditions, there was a 1.4-fold decrease in spore densities on bands after a week, corresponding to a reduction in SLF infection over time. Additional tests also demonstrated that SLF exposed to fungal bands rarely transmitted B. bassiana to other, untreated SLF (∼2% infected). Overall, this work demonstrates that fungal bands can successfully kill and infect SLF. Further work is needed to improve the longevity of fungal bands, maximise spore delivery to insects, and determine the number of bands required to provide control in managed areas.