canada africa partner reservation Spotted lanternflies are a major threat to vineyards. Center County wineries are on alert

Spotted lanternflies are a major threat to vineyards. Center County wineries are on alert

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Grape growers take note: Spotted lanternflies could be on the rise in Center County this summer. Although the invasive locust from Asia is mainly known as a nuisance rather than a destructive force on trees and plants, it could have a damaging effect on Happy Valley’s vineyards if a large population emerges this season, experts say.

Last summer, Center County residents reported seeing spotted lanternflies 529 times, according to data from the Pennsylvania Department of Agriculture. That’s an increase of more than 500% from the summer of 2022, when residents reported seeing the invasive pest 79 times, and an increase of about 1,000% from 2021, when residents reported 44 sightings.

The PDA added Center County to its quarantine zone in 2022, which regulates the movement of vehicles that could harbor the insect. Introduced to North America in Berks County in 2014, the lanternfly is a notorious hitchhiker on cars, boats and trucks traveling on highways. In 2024, all but the 15 northernmost Pennsylvania counties were placed under quarantine.

A spotted lanternfly infestation is noticed immediately, noted Brian Walsh, a Penn State Extension educator and spotted lanternfly researcher. Adult lanternflies bump into people, usually at eye level, and swarm around neighborhood trees and outdoor events. They also secrete honeydew, a euphemism for liquid feces, which can then grow a type of black, sooty mold that stains patios and furniture.

But the nuisance problem — hundreds or thousands of inches long insects seemingly crawling on everything, Walsh said — isn’t his biggest concern.

“When the lanternfly first arrived here, there was a lot of fear that it would attack our hardwood forests,” Walsh said. “We understand a lot more now – we are only about a decade after the discovery – and we now recognize that the biggest threat to agriculture is the grape industry. Most farms will be able to weather it, but grape growers could even lose their vineyards if they don’t respond properly to the invasion.”

Vince Burkle, of the Indiana Department of Natural Resources, holds an adult spotted lanternfly found in Huntington, Indiana, on August 17, 2022. (Andy Lavalley/Post-Tribune/TNS)Vince Burkle, of the Indiana Department of Natural Resources, holds an adult spotted lanternfly found in Huntington, Indiana, on August 17, 2022. (Andy Lavalley/Post-Tribune/TNS)

Vince Burkle, of the Indiana Department of Natural Resources, holds an adult spotted lanternfly found in Huntington, Indiana, on August 17, 2022. (Andy Lavalley/Post-Tribune/TNS)

The hardwood trees can withstand several years of attack and not be killed right away, according to Walsh, while vines generally cannot withstand the heavy feeding of lanternflies in one season.

“From what we’ve seen so far, it typically takes two to three consecutive years to reach a large population of lanternflies in a vineyard,” says Michela Centinari, associate professor of viticulture at Penn State. “It’s not something that happens overnight. It is very difficult to predict how lanternflies behave, but we know that vines are one of their favorite habitats. We expect there will be more lanternflies around the vineyards this year, around Center County and other parts of the state.”

A learning curve for grape growers

Over time, in Berks County, Philadelphia and elsewhere, experts have seen lanternfly populations increase for three to five years, peak and then decline. That’s equivalent to the time it takes a large population to destroy a vineyard.

Spotted lanternflies are phloem feeders, Centinari said, meaning they feed on the sap in the stem and trunk of the vine, not the leaves or fruit.

“You don’t see any direct damage in the vines, unlike biting insects or insects that feed on fruit, where you can see where they are attacking the plant,” says Centinari. “It is very difficult to see the damage while the lanternflies are attacking a plant, but the year after a major infestation we see dead vines in vineyards.”

Centinari said controlling a pest is a learning curve for grape growers, especially around harvest time. The nymph stage of the lanternfly life cycle, which occurs early in the growing season in May, is not as much of a problem for vineyards as the adult stage, in September and October.

Marquette grape vines at University Wine Company on Tuesday, April 30, 2024.Marquette grape vines at University Wine Company on Tuesday, April 30, 2024.

Marquette grape vines at University Wine Company on Tuesday, April 30, 2024.

“There may be thousands of adult lanternflies, all arriving around harvest time, when it is more difficult to know when to spray insecticides to prevent spraying on the fruit,” Centinari said.

Gene Proch, owner of the University Wine Company in Harris Township, said that while he has yet to experience vineyard damage from the spotted lanternfly, he saw about 100 adult lanternflies on the property around his winery building last year.

“The question is, did the adult flies I saw on the property at the end of the summer make it out and lay eggs somewhere?” said Proch. “I don’t know, but we will be looking for nymphs in the vineyard this spring and early summer because they really attack vines.”

Proch said he’s concerned about spongy moths, formerly known as gypsy moths, which he thinks will be a bigger problem for Happy Valley this year than the spotted lanternfly. Spongy moth caterpillars attack tender leaves and destroy trees and plants, including vines.

Baby spongy moth caterpillars on Marquette grape vines at University Wine Company on Tuesday, April 30, 2024.Baby spongy moth caterpillars on Marquette grape vines at University Wine Company on Tuesday, April 30, 2024.

Baby spongy moth caterpillars on Marquette grape vines at University Wine Company on Tuesday, April 30, 2024.

Patton Township sprayed 1,285 acres in the Valley Vista, Park Forest, Homestead Farms, Oakwood and Woodycrest neighborhoods last May to control spongy moth caterpillars, and plans to resume spraying in late May or early June this year.

“Last year we had gypsy moths drifting into the vineyard on their wires, and on Tussey Mountain behind us you can already see brown spots, so I suspect this year will be worse in terms of defoliation,” Proch said. “I’m sure they will do the same to the vineyard if they start using grape vines.”

On the watch

Doug Rogers, winemaker at Happy Valley Winery in Ferguson Township, said he also observed about 100 adult lanternflies around the winery’s buildings last year, but none in the vineyard.

“We looked for egg masses in late summer and early fall, but we didn’t find egg masses where we found the adults,” Rogers said. “I’m hopeful that we won’t have an outbreak this year.”

Rogers said he tries to reduce the risk of mold and disease each spring by burning the waste from pruning, and in doing so he may have burned egg masses he hadn’t noticed.

“All we can do is make sure we spot them early, and if we do see them, monitor the situation and figure out what the best next step is,” he said.

Scott Hilliker, winemaker at Mount Nittany Vineyard & Winery in Harris Township, said he didn’t see any spotted lanternflies last year, but he has put up posters around the winery to keep an eye on customers. His vineyard staff is also trained to proactively look for it.

“I know they’re in Center County, and it’s only a matter of time before they find us on this side of the mountain,” Hilliker said. “We’ve been lucky so far because there’s a lot of traffic coming from other parts of PA, and they can travel, hitch up to a car and fly away. We try to be aware of what is going on and do a good job of educating customers and employees.”

According to Walsh, it is difficult to quantify spotted lanternfly populations because they are millions of moving targets that use many different host plants. Experts still don’t know how far an individual adult lanternfly can fly in a season before laying eggs and dying.

One of the ways experts currently track populations is through citizen reports, although these are not an exact science.

“While citizen reports can help officials respond quickly to new infestations, they can be used anecdotally to know where hot spots are, such as in Allegheny County last year,” Walsh said. “What we don’t know is what the decline rate of reporting is in subsequent years, and we think this is significant, not because lanternflies are not present, but more because of ‘fatigue’ from the pest.”

Center County residents can report lanternfly sightings this season online to the PDA or by calling 1-888-4BAD-FLY (1-888-422-3359).