Local grape-growers are on tenterhooks, in the face of expert warnings that a sap-sucking agricultural vandal – the invasive spotted lanternfly – most likely will descend on their vineyards in the coming spring.
An adept hitchhiker, the pest already has Rappahannock surrounded. First detected in Virginia five years ago, in nearby Frederick County, it has spread through more than 20 counties in the state. It feeds on tree sap and grape vines are a favored food source.
To date, there have been no confirmed sightings, but invasive species specialist Mike Wenger, who works with the Rappahannock League for Environmental Protection, said: “I’m pretty sure they’re in the county. We just haven’t found them yet.”
Mike Wenger describing the invasive species Autumn Olive at bank of the Rush River at the county park. (Photo/Luke Christopher)
Wenger works to educate the public on identifying the insect and the egg masses it leaves behind. Once sighted, the next step, he said, would be to “kill them – and [you] do that by the very technical technique of squishing them. Then [you] call it into the extension office.”
The pest is a danger to orchards too, but Rappahannock’s Virginia Cooperative Extension agent Kenner Love said vineyards are the most at-risk agribusiness.
Love said: “So far, the research has shown that they like to feed on the apple trees, but they’re not showing any significant damage. The vineyards are more susceptible to the feeding and the vines are more susceptible to damage.”
Bill Gadino, owner of Gadino Cellars in Washington, said: “It’s something we have to get under control. They’re not in this county now but I don’t see how we can keep them out.”
Bill Gadino at Gadino Cellars (Photo/Luke Christopher)
For homeowners, the spotted lanternfly also is a nuisance, feeding on backyard trees and secreting a clear, sugary substance referred to as “honeydew,” which attracts bees, ants and wasps and eventually grows a black sooty mold. Reports from heavily infested areas, like Winchester, depict honeydew “raining” from the trees.
An invasion
Indigenous to China, the spotted lanternfly was first detected in the U.S. in Berks County, Pennsylvania, in 2014. The bug spreads rapidly by laying its eggs on vehicles and shipping containers and traveling railways and interstate roads.
“This insect is a very good hitchhiker,” said entomologist Eric Day, who works in the Virginia Tech Department of Entomology. “They were showing up mostly on transportation corridors like I-81 and railroads. It moves along with trucks and trains, unfortunately pretty well.”
See a spotted lanternfly? Wildlife experts advise that you kill it. (Courtesy/Virginia Tech)
The spotted lanternfly has now been identified in 14 northeastern and northern Midwest states.
The Virginia Department of Agriculture and Consumer Services (VDACS) has issued a quarantine notice in an effort to slow its spread.
“We have 13 counties and eight independent cities in the quarantine,” said VDACS agricultural manager Amanda Bly. “Those reflect counties where there is a significant reproducing population.”
Page and Warren counties, both of which border Rappahannock, are among the 13 under quarantine.
The quarantine program operates on a volunteer basis. VDACS requests businesses in quarantined areas to complete an online training course on identification and best management practices. On completing the training, they receive a permit to inspect regulated articles that are stored outdoors – the movement of which could spread the insect further afield.
“One of the most impactful things we can do is prevent [the spotted lanternfly] from moving in the first place,” said Bly.
Quarantine notices have slowed the insect’s spread; but experts believe it cannot be contained.
“I think it’s inevitable that we will see the spotted lanternfly pretty much every place that it wants to go,” said Wenger.
Further efforts from VDACS include educational outreach, surveying, trapping, removing egg masses and treating infested regions with insecticides.
Economic impact
When the spotted lanternfly first arrived in Pennsylvania it quickly devastated the state’s agriculture and forestry. In 2017, a study by the Center for Rural Pennsylvania estimated more than $300 million in losses. Some vineyards were forced to close after losing more than 90% of their yield.
Fortunately, Virginia’s growers have had more time to prepare and experts believe the damage will be far less severe.
“So far, due to the proactive work by the vineyard owners, there’s been very little damage,” said Day. “In Pennsylvania it’s been a little bit of a different story, but at least in Virginia we have not seen any serious damage in vineyards from it.”
An indication of what’s to come can be seen in Virginia’s ground zero, Frederick County, where agriculture extension agent Mark Sutphin has been working to combat the infestation since the spotted lanternfly was first detected in January 2018.
It’s an expensive battle. “Vineyard growers have reported potentially double to triple input costs for managing spotted lanternfly,” he said.
The spotted lanternfly has yet to be detected in Rappahannock County, though local experts warn its presence is likely. If sighted, it is advised to kill the pest and its egg masses and report it to the county’s Virginia Cooperative Extension office.
The surging cost is for the extra insecticides necessary to protect vines. Left untreated, Sutphin said the insect’s feeding would stress the vines, depleting their resources and leaving them susceptible to winterkill.
Dr. Mizuho Nita, a pathologist at the Alson H. Smith Jr. Agricultural Research and Extension Center in Winchester, said there were other negative effects for vineyards, including the bug being an “eyesore” for winery patrons.
The spotted lanternfly spans an inch to an inch and a half.
“It’s very noticeable,” said Nita. “And they jump around, so it can be a potential annoyance issue with the customers.”
Additionally, the sooty mold that develops on the spotted lanternfly’s honeydew secretions could affect the winemaking process, said Nita. Viticulture researchers are still studying this aspect of the infestation.
Nita believes with proper practices grape growers can weather the storm of spotted lanternflies.
“It is an issue, no doubt, but we do have the tools to mitigate the issue,” said Nita. “We don’t have to be in panic mode at this point. We just have to get prepared.”
Mitigation
The ailanthus tree, more commonly known as the tree of heaven, is a favorite food source for the spotted lanternfly, which can be found in abundance wherever the ailanthus tree, also classified as an invasive, is left unchecked.
“Some research indicates a higher preponderance of ailanthus is correlated with a higher preponderance of spotted lanternfly,” said Wenger.
Initially, VDACS and the United States Department of Agriculture (USDA) funded efforts to remove ailanthus trees in affected areas.
Vineyards in the county have also taken it upon themselves to eliminate as many ailanthus trees as possible. Gadino said he and his workers had removed more than 100 around his vineyard in Washington. To do so, they used a “hack and squirt” method – slicing into the trunk with a machete and applying the appropriate herbicide.
Removing ailanthus trees is beneficial beyond tackling the spotted lanternfly. But Love alludes to a potential downside of complete eradication around vineyards.
“If you take them all down there’s no attractive plant there for [the spotted lanternfly] to feed on and there’s more of a tendency for them to find what’s there,” said Love. “And that might be a vineyard.”
He said the tree also might be harnessed as a “trap” for the spotted lanternfly, by injecting larger ailanthus trees with insecticides, potentially killing insects that feed on the tree.
The tree of heaven is so abundant in Rappahannock County, outright eradication would be nearly impossible — so a selective approach is sometimes required.
“The tree of heaven occurs separately, as male and female trees,” said Sutphin. “So, if you can’t remove all of them, we encourage property owners to remove the female trees because those are the ones producing seeds in really high numbers.”
An invasive species, the spotted lanternfly threatens vignerons across Rappahannock County because of their destructive tendencies. (Courtesy/Virginia Tech)
More advanced efforts to reduce infestation include training dogs to sniff out spotted lanternfly egg masses. Nita, who helped spearhead the research with animal scientists at Texas Tech, said the project had finished its first phase, proving that dogs could identify egg masses with near perfect accuracy. Detection dogs would be used to inspect regulated articles in quarantined areas.
The spotted lanternfly thrives in the absence of natural predators. USDA scientists are analyzing several species of parasitoid wasps from China that could help diminish spotted lanternfly populations. However, research to assess possible damages of introducing yet another invasive species could take several years.
More information on best management practices for combating the spotted lanternfly can be found by calling Rappahannock County’s Cooperative Extension office.
“To combat an invasive species like this, it takes really a whole community,” said Sutphin.
