Spotted lanternfly (SLF), Lycorma delicatula, is an invasive planthopper first detected in Ohio in 2020 (Mingo Junction in Jefferson County). Currently, no Ohio vineyards have reported an SLF infestation; however, this pest poses a significant threat to the industry. This invasive planthopper originates from Asia but has been in the United States since 2014. SLF has a broad host range, with over 200 different plant hosts. Many of these hosts are common landscape plants, including tree of heaven, black walnut, maple, and wild grape (Murman et al., 2020). SLF can survive exclusively on cultivated grapes.
Often, spotted lanternflies travel by human transportation, so rail lines, parking lots, and other areas experiencing high traffic should be carefully monitored for the presence of SLF. Vineyards near transportation corridors and/or areas with a large proportion of SLF host plants may be at a higher risk for SLF colonization.
Life Cycle
First instar nymphs emerge from egg masses from late April into June. Early SLF instars (first through third instars) have a black body with white dots (Figure 1). They are very small (4–10 mm), highly mobile, and move quickly when disturbed. Fourth instar nymphs appear in late June and can be found as late as August. This late-stage instar can be distinguished from early instars by its red and black body with white dots (Figure 1). Adults may be found as early as July but peak from late August to mid-October. They are easily identified by their pink forewings and large size (>25 mm). Their namesake comes from the black dots on the pink forewing. They hold their wings tent-like over their body. The bright red underwing is only seen when SLF is moving or threatened.
Females lay egg masses from September into November (Figure 1) (Urban & Leach, 2023). Egg masses contain dozens of eggs (30–50 per mass) and range from 30 to 60 mm in length and 20 to 30 mm in width. Appearance of egg masses is variable and depends on the amount of wax deposited by the female during egg-laying (Figure 2). Egg masses are found on vertical surfaces and vineyard posts or tree trunks surrounding the vineyard. Egg masses overwinter from October to emergence in April–May.
Common Misidentifications
Egg masses are difficult to identify and can be confused for lichen, other insect egg masses, or even mud. However, egg masses typically look brown to gray in appearance and have a claylike texture. The nymphal stages of spotted lanternfly resemble ticks or spiders; however, SLF will have six legs instead of eight. Adult SLF may be misidentified as different moths, including tiger moth, cecropia moth, grapevine epimenis, and the pink underwing. They also can be misidentified as the ailanthus webworm and the eastern boxelder bug.
Damage and Impact of Spotted Lanternfly in the Vineyard
Spotted lanternfly can be found in the vineyard year-round. SLF are sap suckers, feeding directly on grapevine phloem tissue. They have long sharp mouthparts that pierce plant tissue to feed. Initially, early-instar nymphs feed on grape shoots. However, as SLF develops, insects will move onto the cordon and trunk to feed. Heavy SLF feeding can result in reduced photosynthetic potential, decreased sap flow, canopy dieback, and plant health decline (Harner et al., 2022). These negative impacts to grape physiology have also been correlated with a decline in grape yield. High densities of spotted lanternfly (>50 SLF per vine) result in reduced clusters per shoot (Leach & Leach, 2020). SLF also excrete honeydew, a sugary substance that serves as a medium for sooty mold production on leaves. While sooty mold is not directly pathogenic to grapes, it will block leaf photosynthesis. Further, honeydew can contaminate fruit, leading to decreased fruit quality and an increased prevalence of flies, bees, and wasps (Urban, 2020). Long-term research is still needed to quantify the broadscale impacts of SLF within vineyard systems, including impacts to overwinter injury, marketable yield, and plant physiology.
Monitoring
Currently, monitoring is one of the best approaches to slowing the spread and impact of SLF (Urban & Leach, 2023). Scouting remains a highly effective way to detect and quantify SLF in vineyard systems. Walk through vineyard blocks once or twice a week, especially during peak adult activity (mid-August to mid-October) (Figure 3). Prioritize vineyard edges, which typically have the greatest abundance of SLF, especially if the vineyard edges have favorite SLF host plants. Younger SLF instars are typically found in the shoot tissue, whereas adults can be found feeding on all plant parts. Canopies often harbor large numbers of SLF and should be carefully inspected for the presence of SLF. Passive sampling approaches like sticky bands wrapped around tree trunks or circle traps can also assist in monitoring for SLF. However, improper site selection may lead to false negatives or underestimated vineyard populations.
Management Options
Consider the landscape. Spotted lanternflies appear to be influenced by the presence of favored host plants and proximity to human transportation corridors. If the vineyard block is close to a transportation corridor and/or is densely vegetated with the tree of heaven, pest pressure may be higher. Managing the plants within the landscape (e.g., removing tree of heaven) may decrease the SLF population success within the area.
Treat infestations. Both high nymphal and adult populations warrant management. However, adults have been implicated in causing the most damage to grapevines. Management is often needed close to harvest (outbreaks peak in September and October), which necessitates careful considerations of preharvest intervals. A variety of insecticides can control SLF populations, including products from neonicotinoids, pyrethroid, and organophosphate classes. Pyrethroids currently have the longest residual insecticide timeframe and perform the best, but neonicotinoids also offer excellent control. Currently, thresholds are not established for spotted lanternfly; however, a provisional threshold of five SLF per vine has been implemented in other areas in the United States. Consider preferentially treating vineyard perimeters, which often harbor the greatest number of SLF. Recent research indicates that this approach is statistically similar to treating the entire vineyard block.
Look out for egg masses. Vineyards are ideal sites for SLF oviposition. The destruction and removal of egg masses in areas with smaller populations can be an alternative to relying on chemical control of adults (Urban & Leach, 2023). Scraping egg masses can increase egg mortality and reduce overwintering populations. Ovicides can be used to treat masses, including paraffinic and/or mineral oils.
Keep it covered. Netting vineyard blocks can physically exclude SLF from canopies and reduce the overall impact of infestation (Leach et al., 2023). Netting must be closed tightly around the rows and cover the trunk to ensure that SLF do not move onto the plant. However, this approach is often costly, so try to prioritize this practice in especially vulnerable blocks.
Additional Resources
For more information on evidence-based pest management practices, go to ahsleybleach.com.
References
Harner, A. D., Leach, H. L., Briggs, L., & Centinari, M. (2022). Prolonged phloem feeding by the spotted lanternfly, an invasive planthopper, alters resource allocation and inhibits gas exchange in grapevines. Plant Direct, 6(10), e452.
doi.org/10.1002/pld3.452
Leach, A., & Leach, H. (2020). Characterizing the spatial distributions of spotted lanternfly (Hemiptera: Fulgoridae) in Pennsylvania vineyards. Scientific Reports, 10(1), Article 20588.
doi.org/10.1038/s41598-020-77461-9
Leach, H., Mariani, T., Centinari, M., & Urban, J. (2023). Evaluating integrated pest management tactics for spotted lanternfly management in vineyards. Pest Management Science, 79(10), 3486–3492.
doi.org/10.1002/ps.7528
Murman, K., Setliff, G. P., Pugh, C. V., Toolan, M. J., Canlas, I., Cannon, S., Abreu, L., Fetchen, M., Zhang, L., Warden, M. L., Wallace, M., Wickham, J., Spichiger, S.-E., Swackhamer, E., Carrillo, D., Cornell, A., Derstine, N. T., Barringer, L., & Cooperband, M. F. (2020). Distribution, survival, and development of spotted lanternfly on host plants found in North America. Environmental Entomology, 49(6), 1270–1281.
doi.org/10.1093/ee/nvaa126
Urban, J. M. (2020). Perspective: Shedding light on spotted lanternfly impacts in the USA. Pest Management Science, 76(1), 10–17.
doi.org/10.1002/ps.5619
Urban, J. M., & Leach, H. (2023). Biology and management of the spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae), in the United States. Annual Review of Entomology, 68, 151–167.
doi.org/10.1146/annurev-ento-120220-111140
Want more information on how to best care for your grapevines? Extension Publishing offers these for-sale publications:
Spring Frost Injury of Grapevines and Protection Methods
Midwest Grape Production Guide
Midwest Home Fruit Production Guide