Dispersal of Lycorma delicatula (Hemiptera: Fulgoridae) Nymphs Through Contiguous, Deciduous Forest.

Spotted lanternfly (Lycorma delicatula) is a recently introduced pest in the United States, where it threatens the wine, timber, and ornamentals industries. Knowledge of the dispersal ability of L. delicatula is key to developing effective management strategies for this invasive pest. We conducted a mark, release, re-sight study, marking nymphs with fluorescent powders and observing dispersal distances from a central release point at three time points over 7 d following release. To examine how dispersal patterns changed over the course of nymphal development, we repeated this process for each of L. delicatula's four instars. All releases were conducted in contiguous, deciduous forest, which is a widespread habitat type within L. delicatula's invaded range and a habitat where this pest may have negative ecological and economic impacts. We found that nymphs displayed clear directionality in their movement following release, apparently preferring to move uphill on the modest 6° grade at our release site. Most nymphs remained near the release location, while some moved tens of meters. The maximum displacement we observed was 65 m from the release point, 10 d after release. Nymphs were re-sighted singly and in small groups on a variety of trees, shrubs, and understory vegetation. All four instars had similar dispersal distances over time, though third instar nymphs moved farthest on average, with estimated median displacement of 16.9 m 7 d after release. Further studies are needed to provide additional information on what factors influence spotted lanternfly dispersal.