Vineyard helping researchers understand damage lanternflies can do

Winery owner Darvin Levengood is no fan of the spotted lanternfly, an invasive insect that can wreak havoc on grapes.

But if there’s one thing he really can’t stand, it’s the term people have come up with for the sweet, sticky substance the bugs excrete: honeydew.

“Honeydew is an edible fruit everybody loves … it’s nothing more than the poop of the lanternfly,” he said. “It’s, I think, misnamed.”

He goes on to explain that when the sweet substance is left behind on grapes and grape vines, it attracts ants, wasps, bees and fungus.

“It’s a multipronged nuisance, actually,” he said.

Little is known about the spotted lanternfly and the full extent of damage the insect — and its honeydew — can do.

But a study that’s taking place on Levengood’s Manatawny Creek Vineyards in Amity Township, Berks County, aims to find out.

There, Penn State researchers are wrapping cages around up to 80 individual grape vines to find out whether farmers should fret at the sight of as few as five of the bugs or hold off until they see 100 or more.

Erica Smyers, a Ph.D. candidate leading the project, said she wanted to give farmers a sense of how they should plan their pest management strategies.

So this summer, she will be introducing different numbers of insects onto each of the vines of the plants she has caged. Over the course of the summer, a team will check to see how much damage is wrought by the spotted lanternflies.

“We don’t know a lot of things about these insects yet,” Smyers said. “[Grapegrowers] need to know how bad of a problem they’re going to be and how it’s going to impact their vines so they can make their pest management decisions, because for a lot of growers, they can’t afford to spray, they can only apply certain insecticides so many times a year and it can be really expensive.”

The spotted lanternfly, which is a native of Asia, was first discovered in Berks County in 2014 and since then has spread to 13 counties in Pennsylvania, including Lehigh and Northampton.

Those areas are under quarantine, meaning anyone who travels needs to check their vehicles and any items being moved for the bugs, as well as their egg masses, which resemble splotches of mud, to make sure they don’t spread the insect further.

The bugs pose a threat to $18 billion worth of agricultural commodities produced in the state, according to state officials.

Officials are so worried that the U.S. Department of Agriculture recently announced $17.5 million in emergency funding to fight the blighters, some of which is going toward Smyers’ study.

Smyers said she and a team will go out and catch the insects and then move them into the cages. They won’t be able to escape, she said.

She hopes to observe exactly how much damage the spotted lanternflies do. They’ve been known to hurt vines in a number of different ways: the bugs feed on the plants and make wounds with their piercing, sucking mouth parts. Smyers said they’ve been known to stunt vine growth.

The wounds leak sap and the bugs excrete honeydew. Both attract other nuisance insects like wasps, ants and bees.

The honeydew also attracts sooty mold, which grows on grapes and vines, attracts more pests, and acts as sunblock for the plant.

Smyers said it’s not known what impact it has on wine or grape juice — that’s the subject of another experiment. Several experiments are looking at the basic biology of spotted lanternflies, insecticides and other aspects of the bugs, she said.