Spotted lanternfly, Lycorma delicatula (White), is an invasive Asian insect that was initially found in Berks County, Pennsylvania, in 2014. As of early 2020, this pest had been found in five more eastern states and it is expected to continue to expand its geographical range. Lycorma delicatula is highly polyphagous but seems to prefer tree-of-heaven, Ailanthus altissima. However, grape growers in Pennsylvania have reported significant damage and loss of vines caused by L. delicatula adults. In fall 2018, two fungal entomopathogens (Beauveria bassiana and Batkoa major) drove localized collapses in L. delicatula populations in Berks County, Pennsylvania. In 2019, we tested applications of a commercialized mycoinsecticide based on B. bassiana strain GHA on L. delicatula populations in a public park in southeastern Pennsylvania. A single application of B. bassiana reduced fourth instar nymphs by 48% after 14 d. Applications of B. bassiana to L. delicatula adults in the same park resulted in 43% mortality after 14 d. Beauveria bassiana spores remained viable on foliage for 5–7 d after spraying. We also conducted semi-field bioassays with B. bassiana GHA (formulated as BoteGHA and Aprehend) and another mycoinsecticide containing Isaria fumosorosea Apopka Strain 97 against L. delicatula adults feeding on potted grapes. All the mycoinsecticides killed ≥90% of adults after 9 d using direct applications. Aprehend killed 99% of adults after 9 d with exposure to residues on sprayed grapes. These data show that fungal entomopathogens can help to suppress populations of L. delicatula in agroecosystems and natural areas.

The spotted lanternfly, Lycorma delicatula (White), is a new invasive pest in the United States. To quantify spotted lanternfly population abundance, one must understand this pest’s dispersion pattern, that is, the spatial arrangement of individuals within a population. Spotted lanternflies overwinter in egg masses from late fall to May, making this life stage suitable for population assessments. We measured the dispersion pattern of egg masses at two types of sites: a suburban housing development, where we used individual trees as the sampling unit, and rural woodlots, where we used individual trees and also plots with 5.64 m radius as sampling units. Plots were the same size as those recommended for monitoring the gypsy moth, a well-studied pest with similar egg laying habit to the spotted lanternfly. Egg masses in both sampling units were counted up to a height of 3 m. With trees as the sampling unit, egg masses were aggregated in 12 of 20 rural sampling universes, randomly dispersed at 6, and completely absent at 2. Similar patterns were seen when using the 5.64-m radius rural sampling units and for suburban sampling universes. We calculated sample size requirements for a range of mean densities at a precision of 25 and 30%. Additionally, the vertical distribution of egg masses was characterized on the invasive tree of heaven [Ailanthus altissima (Mill.) Swingle], a preferred host for spotted lanternflies. For small trees, there was a positive relationship between number of egg masses in the bottom 3 m of the tree and the total count.

The spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae) (White, 1845), is an invasive pest in the Mid-Atlantic region of the United States. Understanding this pest’s dispersion patterns is fundamental for development of management and surveillance programs. To address this knowledge gap, we quantified spotted lanternfly nymph dispersion patterns by instar for rural and urban/suburban habitats, and we compared the number of sample units required for sticky traps and in situ visual counts to estimate population densities at several precisions. In addition, we assessed the ability of two experimental designs (completely random and randomized complete block) to detect management practices’ impacts in the field. All instars typically followed an aggregated dispersion pattern. Sample size and time requirements for checking and replacing sticky traps and for conducting in situ counts were similar, but in situ counts do not require purchasing traps, installation time, or delays before treatment, and do not remove insects. Although the cost for using in situ counts is likely less than for sticky traps, early instar spotted lanternfly nymph populations are harder to visually detect than later instars because of their small size, which may negate any cost advantage when treatments are applied early. In general, using a randomized complete block design resulted in higher statistical power than a completely random design, allowing detection of proportional population reductions of 10–20% less with equal replication. Studies aiming to evaluate treatments that reduce spotted lanternfly numbers by less than 60% will require researchers to evaluate the feasibility of using the required large sample sizes.

Developing a lifelong marking method for Lycorma delicatula (White, 1845) is crucial to investigate ecological processes. Here we validate a marking method using stable isotope enrichment (15N) of host plants to track spotted lanternfly (SLF), an invasive species causing economic damage on grapes, hardwood forest and landscape tree species. To validate this method, we first determined the isotope dosage to be sprayed on the host plants and subsequently detected in SLF. Second, we examined whether 15N mark remains detectable from the nymphal to adult stage. We demonstrated that two stable isotope dosages applied to the host plants were assimilated by the insect and equally detectable in the exoskeleton, wings, and mature eggs ready to be oviposited. This safe and reliable method can be used to examine fundamental processes of the biology and ecology of SLF that range from dietary resources and resource allocation to food-web structure and dispersal patterns.

Management to control the spotted lanternfly, Lycorma delicatula (White), would ideally achieve managers’ goals while limiting impacts on nontarget organisms. In a large-scale field study with 45 plots at least 711 m2, we tested foliar applications of dinotefuran and 2 formulations of Beauveria bassiana (Balsamo) Vuillemin, each applied from the ground and separately by helicopter. Applications targeted early instar nymphs. For both application methods, a single treatment with dinotefuran significantly reduced L. delicatula numbers, as measured by catch on sticky bands (91% reduction by air and 84% reduction by ground 19 days after application) and by timed counts (89% reduction by air and 72% reduction by ground 17 days after application). None of the B. bassiana treatments significantly reduced L. delicatula numbers, even after 3 applications. Beauveria bassiana infection in field-collected nymphs ranged from 0.4% to 39.7%, with higher mortality and infection among nymphs collected from ground application plots. Beauveria bassiana conidia did not persist for long on foliage which probably contributed to low population reduction. Nontarget effects were not observed among arthropods captured in blue vane flight intercept traps, San Jose Scale pheromone sticky traps or pitfall traps, but power analysis revealed that small reductions of less than 40% may not be detected despite extensive sampling of 48,804 specimens. These results demonstrate that dinotefuran can markedly reduce local abundance of L. delicatula with little apparent effect on nontarget insects when applied shortly after hatch, and that aerial applications can match or exceed the effectiveness of applications from the ground.