This spring, a new insect scourge is hatching, its distinctive black-and-white nymphs emerging from a hard-to-spot gray mass of eggs on trees and rocks, even rusty metal. The Spotted Lanternfly is a serious threat to orchards, forests, and especially vineyards, and can reduce fruit yields by 60 to 70 percent. At the top of its menu, though, is the “tree of heaven,” Ailanthus altissima, an invasive species.
The bugs are not fussy, though. They feed on the sap of dozens of trees and plants, delivering a kind of double whammy. Not only do they desiccate everything they feed on, but their excrement attracts a mold that also weakens and kills the host. They’re a very real threat to Virginia’s grape-growing, tree fruit, hardwood, nursery and landscape industries.
The good news: Albemarle County probably has a year or so before the fly population increases, said Carrie Swanson, a senior extension agent with Albemarle County. Last year, an alert hiker spotted an adult on the Rivanna Trail. “That’s probably a one-off,” Swanson said. “They hitchhike via railways, cars, backpacks, really anything, and can both walk and fly from plant to plant.”
She finds hope in the fact that Winchester, where the fly was first spotted in 2018, has yet to see significant damage. In Pennsylvania, though, where the first pest was found in 2014, there’s a huge amount of destruction as the nymphs and adults chew their way through trees and vines. Since then, the clownish adults––much easier to spot than the nymphs––have been identified in Warren, Page, and Shenandoah Counties, with one report of an egg mass in Nelson, and one adult in the Belmont neighborhood of Charlottesville. The stately pace at which the lanternfly is marching south has given the Virginia agriculture network a little time to figure out what to do.
“Our wine growers and orchardists are certainly braced for this,” Swanson said. “Now we’re trying to educate the public.” What the public can do is to be watchful for the egg masses and the hatching nymphs. “Do not spray the eggs,” she said. “It won’t work, and we don’t want to kill pollinators along with the pests.” Scientists are working to identify oils that may be harmless to pollinators but fatal to the lanternfly eggs.
In Pennsylvania, a widespread campaign has enlisted citizens to look for the masses and dispatch them using a credit card, with videos showing them how to make sure the eggs are properly killed. Swanson advised taking a photo to send to the Albemarle Extension Office so agents can monitor the spread; and then scrape the egg mass into alcohol (Pennsylvania also recommends dunking them into hand sanitizer) both of which will prevent the eggs from hatching. Those with many tree-of-heaven plants can remove them, although keeping one or two can help orchardists monitor the presence of the fly on their property.
Learning from the experience of agents in the more northern areas, Virginia Extension staff members have found some spray protocols work once the eggs hatch, and are working on other control measures. Meanwhile, Swanson said, we all need to support local agriculture by spotting the spotted lanternfly and reporting its location.
There’s an enormous amount of information about the spotted lanternfly on the extension office website: albemarle.ext.vt.edu.