Evaluating multiple sampling methods to delimit outlying spotted lanternfly (Lycorma delicatula) populations

The spotted lanternfly (Lycorma delicatula) is a rapidly spreading invasive pest that causes dramatic productivity losses in vineyards and creates nuisances for homeowners by producing large volumes of honeydew which can promote the growth of sooty mold on decks and outdoor furniture. Long distance dispersal aided by accidental human transport has led to the establishment of satellite populations beyond the boundaries of the large invaded area centered in southeastern PA. Future efforts to limit the spread of this pest may critically depend on managers ability to rapidly locate such satellite populations, delimit their extent, and carry out necessary management to locally eradicate the spotted lanternfly. To test the sensitivity of detection methods, we monitored satellite populations in Altoona, Huntingdon, and Shippensburg, PA throughout the season from March to October. We tested methods including unaided egg mass counts, binocular-aided egg mass counts, visual search for nymphs and adults, Bug Barrier trapping, and trapping with circle traps. Densities of spotted lanternflies at these locations were highest near a central location and declined as distance from the center increased. Generally, search methods produced similar results with regard to the presence or absence of spotted lanternfly and the relative abundance of spotted lanternflies. Our improved estimates for search methods’ sensitivity at low densities should inform future sampling plans as new satellite populations emerge. Ongoing sampling will aim to track the growth or decline of these satellite populations.