In certain locations in the northeastern part of the country a newly introduced invasive species is causing havoc on plant life, and researchers say the spotted lanternfly could pose a problem for hop bines.
The spotted lanternfly, known as Lycorma delicatula, came to the United States from Asia and was first detected in 2014 in Pennsylvania, but likely arrived two or three years earlier. Researchers predict it could have arrived on bundles of stone, as its egg mass, which resembles brown or gray dirt, can easily stick to most surfaces.
The colorful winged creatures look like moths and have coloring similar to ladybugs but “are not flies at all, they are planthoppers,” says Dr. Julie Urban, a research associate professor for the department of entomology at Pennsylvania State University. “Their closest relatives are cicadas, and their mouth parts are like straws that they stick in plants and feed on sap.”
What makes the spotted lanternfly so problematic is that they feed on a broad range of hosts, says Urban. To date the bug has been known to feed on more than 100 species of plants in North America, including grape vines and hop bines.
There are a few other things that make them a problem, Urban notes. While spotted lanternflies are not great flyers, they can move around a lot during their life cycle and will feed on whatever is around while doing so.
When the spotted lanternfly was introduced to South Korea in 2004 scientists noticed that the bug was especially fond of tree of heaven, apple trees, and stone fruit timber.
“Because of that, when it showed up here it rang alarm bells in the agriculture industry,” Urban said.
Spotting Lanternflies and Stopping the Spread
Over the last few years there has been research into ways to prevent the bug from spreading, supporting at-risk plants, and a public awareness campaign urges residents of 14 states including Connecticut, Delaware, New Jersey, and New York, to squish the insect on sight, something that can prove difficult as the hoppers are quick to avoid oncoming feet.
Online tutorials on how to build easy traps have proven helpful for especially hard hit areas.
A spotted lanternfly egg mass is hard to see.
“Detecting them is really challenging,” says Dr. Kelly Oten, an Assistant Professor and Extension Specialist at the Department of Forestry and Environmental Resources at North Carolina State University.
They don’t really look like eggs, Oten notes. Instead, an egg mass resembles a splatter of mud and blends in well with trees or stones. Each mass can contain 30 to 40 eggs.
After hatching, the nymphs, which are black and white and stick close to the ground, are quick to move from under feet. Later in the nymph stage, a bold red pigmentation appears on the body. Adults take on tan, red, and white markings on their wings, but are still hoppers more than flyers.
“We suspect egg masses are being laid on vehicles and other things that move, like train cars,” says Oten. “They move at every stage of life, like hitchhikers. One study that was done here at NC State suggested that they could get to the west coast by as early as 2027.”
The spotted lanternflies use piercing, sucking mouthparts to feed on the sap inside of plants.
“That weakens the plant and predisposes them to other things,” says Oten, noting that the damage can render grapes and other plants incapable of withstanding winter temperatures. “Because the lanternflies are feeding on the sap, a lot of sugar and water is excreted on the other side as excrement, which is called honeydew.”
The honeydew, says Oten, is deposited onto the exterior of the plants and encourages mold growth, which can block photosynthesis. The mold can also contaminate other crops and attract stinging insects.
Tree of heaven, an invasive plant, is the preferred host for the spotted lanternfly, which might come as good news for landowners who view the leafy tree as a nuisance. But the spotted lanternfly also feeds on grape vines.
“They’ve had major impacts to the vineyard industry, the wine making industry,” Oten says. “They also feed on hops. But the reports coming out of the field and during scouting, indicate that the populations aren’t going to be as high [in hop fields] as they’ve seen in vineyards.”
Oten says that scouts monitoring spotted lanternfly spread at farms that have both grape vines and hop bines will see maybe five to 10 spotted lanternfly on a hop plant as compared with hundreds on grape vine.
But with any invasive species things can change at any time, she notes. There is not enough data at the moment to say if spotted lanternflies would prefer different varietals of hops than ones found outside of eastern states, or would swarm towards hop plants without other options.
“Obviously a big concern is the fact that they put off this sooty mold. If you get sooty mold on the cones, it contaminates and makes it unusable for beer production,” Oten says. “We don’t have a crystal ball to guess what will happen but it would be very bad news for this to spread because it can start impacting hop growers.”
Already there have been isolated sightings in Washington and Oregon, two of the top hop-growing states in the U.S.
“If you see them, kill them,” says Oten. “Also if you’re in an area where spotted lanternfly is not known to occur, report it to the state department of agriculture because then we have a much higher likelihood of getting a small infestation under control than we do a large infestation.”