Assessing the effects of volatile repellents on the invasive spotted lanternfly, Lycorma delicatula (White)

Spotted lanternfly [Lycorma delicatula (White)] (Hemiptera: Fulgoridae) (SLF) is a large piercing-sucking insect, native to Asia and newly invasive to the United States. Since its arrival in Pennsylvania in 2014, SLF has spread to 15 additional states and has damaged a variety of ornamental plants, trees, and fruit crops: most notably, grapes. SLF is predicted to have devastating consequences to agroecosystems and forests, demanding improved understanding of its ecology. While classical insecticides are somewhat effective, the ability to repel SLF from crops is of greater importance to prevent initial infestations. Volatile plant secondary metabolites are used to repel arthropods in many agricultural contexts. By utilizing Petri dish-based choice assays, we tested the efficacy of six different plant-derived compounds to repel SLF nymphs. Three repellents (lavender essential oil, CNR-1 blend, and apritone) were found to be most effective. We then evaluated to what extent adult SLF responded to these repellents under semi-field conditions when mixed into a SPLAT® polymer matrix during August 2022.  Significant repellent effects were found for applications of lavender oil and CNR-1 but not for apritone against SLF in the presence of potted grapevine [Vitis vinifera ‘Riesling’].  Most recently, we tested the response of adult SLF in vineyards [Vitis hybrid ‘Traminette’ and Vitis vinifera ‘Syrah’] with high SLF infestation to CNR-1 and lavender oil when mixed into a SPLAT® polymer matrix during September 2022.  Significant repellent effects were found for applications of lavender oil but not for CNR-1 on both varieties of grapevine.