Spotted Lanternfly, the Newest Invasive
A new invasive pest entered our state in January of 2018 called the Spotted Lanternfly, Lycorma delicatula. By the fall of 2019, it had spread over 40 to 45 square miles (about 26,000 acres) in Northern Virginia, specifically Frederick County. At this time, we are not seeing major populations affecting our commercial agriculture production, but Virginia Cooperative Extension warns that the pest “has great potential to impact the state’s grape, orchard, logging, tree- and wood-product, and green industries.”
Vineyards are particularly at risk. “Our knowledge of impact in vineyards is based on experience in Pennsylvania, where yield reductions of 80-90% have been reported from current year feeding once populations become established,” according to a VCE report. “Heavy feeding has resulted in death of most vines, with surviving vines failing to set fruit.”
The Spotted Lanternfly can harm our crops and the atmosphere of our yards and gardens if the populations become dense. Damage to trees and crops include “oozing sap, wilting, leaf curling, and tree dieback.” As the pest congregates in masses, they leave behind large secretions of honeydew. This is a great food source for sooty mold, a black mold that that coats the tops of leaves and can cause plant damage. Some communities in Pennsylvania have reported an interruption to their warm weather outdoor activities due to Spotted Lanternfly. Large populations “will cover trees, swarm in the air, and their honeydew can coat decks and play equipment.” Read more from the Pennsylvania Department of Agriculture.
The Spotted Lanternfly first entered the United States in 2014 and is believed to have traveled here from China, India, or Vietnam via shipments of hardscaping stone. At both the nymph and adult stages, the insects are “phloem feeders,” meaning they suck sap from young stems and leaves. If a vine is not killed outright, it becomes vulnerable to winter mortality. In the home landscape, nymphs tend to feed on smaller, new-growth sections of trees and vines, and young trees with heavy infestations show symptoms of flagging, wilting, and branch death. As adults, the insects will feed on any part of the tree and can cause black weeping wounds along the trunk.
Because of the insect’s ability to hitch-hike on vehicles, management efforts include a travel quarantine up and down Interstate 81. Truck drivers traveling through the quarantined areas must hang a special permit in their window that shows they are educated on this issue. State troopers are trained to recognize these permits and inspect vehicles for Spotted Lanternfly egg masses. Pennsylvania, Virginia, Maryland, and New Jersey are the only Eastern states with established populations at this time, but other states have seen single adults in their communities.
In Northern Virginia, the pest has been sighted outside of orchards and vineyards, but at low population levels so far. The Virginia Department of Agriculture and Consumer Services (VDACS) and the Virginia Tech Entomology Department have been closely tracking the insect and have been working vigorously to eradicate host plants to help control its population. We are achieving 40–60% control efforts as of last year, but realistically, we will not be able to eradicate this new pest or hold the population as is without achieving 90% control. The most we can hope for is reducing population size and helping slow its spread while we learn how to treat for it.
VDACS and Virginia Tech have also worked tirelessly to learn more about the Spotted Lanternfly’s life cycle. There are four stages: egg, first nymph (molts three times), second nymph (large and different color), and finally adult insect. It was thought that tree-of-heaven (Ailanthus altissima) was the preferred host of the first nymph. Now we are seeing the pest on black walnut, red and silver maples, Virginia creeper, and oak trees.
The Entomology Department at Virginia Tech is working with volunteer groups (Master Gardeners, Master Naturalists) and professionals (Department of Forestry, etc.) to monitor this pest throughout Virginia during the growing season. Citizen scientists can place monitoring material on their property and check the insect traps once a week. This data is then entered into an app developed by Virginia Tech in real time. It records where, when, and the specific stages of the insect’s lifecycle observed.
To learn more, please visit the Virginia Cooperative Extension web page devoted to the Spotted Lanternfly. If you think you’ve seen the Spotted Lanternfly, please contact our Horticulture Help Desk at 434-872-4583 or at firstname.lastname@example.org. Our Program Assistant, Melanie Feldman, at 434-872-4582 or email@example.com, can also help with Spotted Lanternfly-related questions.
Virginia Cooperative Extension YouTube Webinar: May 21st SLF Webinar