Management of Spotted Lanternfly (Lycorma delicatula) Overwintering Egg Masses and Multiple State Records of Aculops ailanthi, the Potential Biological Control Agent of Tree-of-Heaven (Ailanthus altissima)

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Virginia Tech


The spotted lanternfly (Lycorma delicatula) overwinters in egg masses for approximately eight months a year, representing the longest individual life stage. The immobile egg mass life stage constitutes a good candidate for management practices. Many insecticides and biopesticides have been demonstrated to provide control of nymphal and adult L. delicatula, but more research is needed on managing SLF egg masses. I conducted bioassays across three years (2021–2023) utilizing various insecticides and biopesticides against untreated and water checks at different application timings on SLF egg masses. Furthermore, in 2023, field trials of malathion and Beauveria bassiana biopesticides were investigated. I found substantial hatch reduction from malathion in all bioassays and field trials. Other pesticides tested in laboratory bioassays demonstrated varying hatch reductions across application timings and years. Laboratory bioassays suggested a single commercially available application of B. bassiana made directly on overwintering L. delicatula egg masses could subsequently infect hatching neonates. In laboratory studies, the optimal timing of spray applications on L. delicatula egg masses was approximately two weeks before hatch. Both field trials demonstrated that infection in hatching L. delicatula nymphs was greater than in laboratory bioassays. The intention of this research is to provide stakeholders with additional environmentally friendly tools to manage spotted lanternfly. In separate studies, I report the first detections of Aculops ailanthi, an exotic mite on tree-of-heaven, Ailanthus altissima, from Montgomery County, Virginia, and Wayne County, Michigan, USA. Samples from both states were sent to USDA-ARS for identification, and scanning electron microscopy confirmed the species as A. ailanthi based on the morphological features. Moreover, I describe the impacts that high populations of A. ailanthi can have on Ai. altissima, in greenhouse settings, and its potential use as a biological control agent. I investigated the efficacy of various foliar insecticide treatments against A. ailanthi on potted Ai. altissima saplings to produce additional management recommendations for researchers struggling to cultivate Ai. altissima in greenhouse conditions due to the overwhelming injury produced by A. ailanthi. All pesticide treatments significantly reduced A. ailanthi populations and provided residual control for two weeks.



Spotted lanternfly, Lycorma delicatula, Aculops ailanthi, Tree-of-Heaven, Ailanthus altissima, Ovicide, Pesticide, Biopesticide, Biological Control, Invasive Species, Integrated Pest Management