Spotted Lanternfly: Winged invasive species poses new threat
A spotted lanternfly isn’t much bigger than a small moth. But the invasive species that has steadily increased its population in the eastern part of the state could make its way westward. (Photo submitted by Pa. Dept. of Agriculture)
Pa. Dept. of Agriculture
Pa. Dept. of Agriculture A spotted lanternfly isn’t much bigger than a small moth. But the invasive species that has steadily increase its population in the eastern part of the state could make its way westward.
Adult spotted lanternflies are seen on an Ailanthus altissima tree, also known as the Tree of Heaven. (Submitted photo)
Submitted photo
Submitted photo The spotted lanternfly lays eggs in a mass as seen above.
Submitted photo
Submitted photo During the fourth life stage of a spotted lanternfly, they appear as small, red nymphs.
Chances are you haven’t heard of the spotted lanternfly — yet. But the invasive species that has steadily increased its population in the eastern part of the state could make its way westward.
A spotted lanternfly isn’t much bigger than a small moth. It’s smaller than a cicada — the most recent swarming insect to hit the area. But the small gray, winged insects are a multifaceted problem, as far as Emelie Swackhamer is concerned.
“We’re worried about our agricultural commodities. We know it can be devastating to grapes and fruit crops — we know that from the experience in South Korea where it was introduced as an invasive species in 2006. It devastated their crops,” said Swackhamer, horticulture extension educator with the Penn State Extension in Montgomery County.
Lanternflies also feed on trees, which leads to concerns about the quality of timber and the overall health of trees. Swackhamer said that then leads to concerns from a trade standpoint.
“We don’t want other states or countries to worry about Pennsylvania timber,” she said.
And noting the experience in South Korea, Swackhamer said they’re worried about the impact the lanternflies would have on the fruit crops and their overall health.
“The insect secretes a sticky substance called honeydew. Mold grows on it, so it reduces the quality of the product,” Swackhamer said. “We already have wine grape growers that have noticed a change in the quality of their grapes and wine.”
The honeydew also contributes to the nuisance factor of the spotted lanternfly. Stinging insects are attracted to the sweet substance — which ironically has a foul odor — and can be a concern for those who have allergies and an overall nuisance for those who don’t like insects, Swackhamer said.
She added that they can also be a nuisance when they swarm — relatively new behavior they observed this past fall during the warmer days.
“They all took flight and they like to be high up on objects, like the warm side of a building or house,” she said. “They’re not trying to get into your house, and they’re not attacking, but the fact that there’s thousands of insects hanging on the sides of your house — they can be problematic.”
Origin
Simply put, Swackhamer said the spotted lanternfly doesn’t belong here.
“It does not naturally occur here, and right now we’re the only place in the western hemisphere that it’s been found,” she said.
The spotted lanternfly, which is originally from Asia, was first found in Pennsylvania in the fall of 2014, though Swackhamer said they believe it had been there since at least 2012 based on the condition of the old, weathered egg masses.
In 2014, they were found in two townships in Berks County, though it was only a matter of weeks before the Department of Agriculture expanded that to five townships.
“As new discoveries were made, they added townships to that area,” Swackhamer said. By 2017, they decided to go on a county-to-county basis. There are currently 13 counties in the eastern part of the state that are listed, though their distribution isn’t evenly dispersed. “Within those 13 counties, there are populations heavier in the center and lower populations in outlying counties.”
They likely spread among the area not because of their own movement (they’re winged, though they’re not especially strong fliers) but because of human’s inadvertent involvement.
“I believe the best possibility for long-range dispersal is that humans inadvertently moved them,” she said. “That’s why there’s a quarantine, to stop the movement of them in life stages.”
She added that they lay eggs on just about anything — trees, rocks, fence posts, patio furniture, etc.
As for how they got here in the first place, Swackhamer said it likely comes back to the fact that we’re in a global trade society.
“They undoubtedly came in commerce,” she said. “Because we’re a global trade society, we’ve become very good at sharing things. And it’s not a one-way movement — we’re moving things to other parts of the world.”
Now that they’re here, Swackhamer said they’re trying to figure out the best management practices, though it’s difficult to do for a number of reasons.
“I don’t think there’s an easy solution. Any impact we’re going to have on eradication efforts will come from multiple tools,” she said.
Researchers are taking a look at promoting the population of other insects that might have an impact on the lanternfly’s population. It may also help to reduce their preferred food source — Ailanthus altissima, an ornamental tree also known as the Tree of Heaven.
Mother Nature may have briefly been on their side, too, to help kill off some of the eggs in the hard, killing frost early last month, Swackhamer said.
“However, while weather events might help us, I don’t believe an exceptionally cold winter will do it because we know they were here and survived during the polar vortex weather pattern,” she added.
Overall, it’s been an interesting couple of years for Swackhamer and others in the field, as she called it a “once-in-a-lifetime type of thing.”
“It’s mostly because of their gregarious feeding behavior. There’s a wide range of plant material, so it makes it difficult to target management strategies,” she said. “Some insects have limited host-range and only lay eggs in specialized spots. But this — it lays them anywhere, which is another part of their behavior that makes it a real challenge.”
Though the spotted lanternfly is still on the other side of the state, Swackhamer said it’s not too early to prepare for their possible arrival.
“Start by identifying the Tree of Heaven and destroying them,” she said, adding that they’re widespread across the state and often found along roadways or train lines. “Those trees are invasive trees from Asia — they shouldn’t even be here. They’re crowding out native plants.”
She recommended finding a professional to destroy the tree rather than simply cutting it down, because they’ll likely resprout. If that’s the case, though, Swackhamer said you must be diligent in cutting the sprouts.
Travelers to and from the area are also asked to be very careful not to move viable life-stages back to their own homes.
“If you have relatives in these counties, don’t move firewood back home, don’t move anything if you can avoid it,” she said. “But if you do move it, inspect them thoroughly — destroy the eggs.”
Swackhamer added that the extension program is currently working with their Penn State Master Gardeners, which are available all over the commonwealth, to educate them on the new insect. They will be available to answer any questions, she said.