ITHACA, N.Y. –– In November, a spotted lanternfly was sighted in Ithaca’s Fall Creek neighborhood spawning fear amongst homeowners and winemakers alike for the havoc the small creature can reap on both backyard trees and expensive grapevines.
If you aren’t familiar with the spotted lanternfly, or Lycorma delicatula, you’re not alone –– neither was America’s scientific community when it first appeared in Berks County, Pennsylvania, in 2014.
Originally from East Asia, infestations across the Northeast have become increasingly harder to control since the pest’s arrival in the United States.
According to scientists, the appearance of the spotted lanternfly in Ithaca has only been a matter of time as the spotted lanternfly moves quickly and quietly across state lines. It’s had isolated sightings across New York state and it may be just a few years until there are serious infestations to deal with.
According to Chris Logue, the director of Plant Industry at the New York Department of Agriculture and Markets, “We do think that, frankly, we’re pretty early in the infestation.”
He added, “I think we have, probably, a very good opportunity to eradicate it or at least manage it and slow the spread.”
The path forward towards preventing a major problem for New York State agriculture comes at a cost from other states, and strategies will continue to evolve as researchers learn more about the spotted lanternfly and how to contain the species’ spread.
“I think of the situation in Pennsylvania; officials there did not have the luxury of another state seeing this first and warning them about it,” Logue said.
Impacts in Pennsylvania
To date, the spotted lanternfly has confirmed infestations in nine states –– with Pennsylvania being the hardest hit by far. It is also the state with the densest infestation and, as a result, has become a major hub of research on the spotted lanternfly. The USDA awarded Penn State a $7.3 million grant in 2019 to support its research.
At the start of 2020, Penn State published a study quantifying the toll the spotted lanternfly is having on the Keystone State’s economy. In total, Pennsylvania is seeing $50 million of revenue lost annually, and it’s estimated that this could rise to $325 million if the spotted lanternfly was able to infest the entire state. The industries losing the most have been Pennsylvania’s hardwood, ornamental plant growers, and especially it’s vineyards. Some grape growers have lost up to 90 percent of their expected yield, and others have gone completely out of business.
According to the state DEC, the impact that the spotted lanternfly could have on New York’s economy is unknown, but the potential damage on the line is no small potatoes; New York State is the third largest wine producer in the country and the combined value of agriculture sectors threatened by the spotted lanternfly is $358.4 million.
Hunting the Spotted Lanternfly
Although notorious for devouring grapes, the spotted lanternfly can feed on over seventy different plant species.
According to Heather Leach, an Extension Associate at Penn State, “You can really think of the landscape as a buffet for them.” But the spotted lanternfly isn’t limited to greenery; it can become ubiquitous in the place’s it’s infested.
In urban and suburban environments it invades people’s property, eating the plants growing there, and it wanders widely, as the people of Philadelphia will confirm. Leach said, “we’ve had reports, in Philadelphia in particular, of them climbing up to this 30 story pool…What we’re finding is that when they come into their adult stage, they’re extremely mobile.”
In its wake, the spotted lanternfly leaves an excrement called honeydew. In areas where spotted lantern fly infestations are dense, honeydew has been compared to rain as it falls from treetops. On plants, the innocuously named waste product promotes the growth of a fungal pathogen, known as black sooty mold. The mold doesn’t directly infect plants, but it blocks them from photosynthesizing, furthering the damage they cause from feeding.
Besides its ability to munch on many native plant species, the spotted lanternfly has a myriad of other reproductive characteristics that make their spread even more likely, including the ability to spawn despite cold temps.
When an adult spotted lanternfly perishes under winter conditions, its egg masses, like a time bomb, withstand the cold until they can hatch in the spring’s warmer weather— each egg mass yielding up to fifty spotted lanternfly nymphs.
Another pernicious talent of the spotted lanternfly is its ability to lay eggs almost anywhere. Since 2014, New York has had protocols in place for curbing and eradicating spotted lanternfly populations. Depending on jurisdiction, Horticultural Inspectors from either the New York Department of Agriculture and Markets, or the DEC, will head to the site where the spotted lanternfly was identified. Once there, they scour the area within a one mile radius in search of egg masses.
But while the adult spotted lanternfly presents a dazzling show of pattern and color, its egg masses resemble little splotches of mud. In addition, the adult species have the novel ability to lay their eggs on seemingly anything, turning cars, packing material, or even backpacks into the spotted lanternfly’s ticket across the U.S. As a result, quarantine zones have been established where there are dense lanternfly infestations and any shipments going in and out of these zones are searched for the pest’s egg masses.
Kelli Hoover, Ph.D., is a professor and researcher in Penn State’s Department of Entomology and has studied the spotted lanternfly’s more traditional breeding ground –– in trees. She co-authored a 2020 paper on where spotted lanternfly egg masses tended to be laid along the trunks and branches. To understand the dispersion patterns of the eggs, Hoover and her team would fell trees in order to count all the egg masses on them and mark how high up they were on the tree.
One of the study sites showed that over 95 percent of the spotted lanternfly’s egg masses were found above 20 feet on the trees. The average height of the trees in this study was about 58 feet. Hoover said, “There’s just not a good relationship between what you can visualize, and count or reach.”
All this considered, there still are places where New York Officials logically began looking for spotted lanternfly eggs, like the tree of heaven, which is not nearly as good a thing as it sounds.
Tree of Heaven: Not as Good as it Sounds
The Tree of heaven, or Ailanthus altissima, deserves its own explanation for being a robust invasive — with some environmentalists granting it the nickname the “tree of hell” — but the ways in which it supports spotted lanternfly populations has elevated concern around it.
In the plant kingdom, the tree of heaven is a chemical warrior. It has chemical defenses that make it inedible for almost all native insects, and it has the ability to secrete chemicals into the soil it’s growing in, suppressing other plants from growing around it.
In the 1800’s, it started off as a popular ornamental plant in the United States, and can now be found almost anywhere in the country. It’s fast growing, and can dominate disturbed habitats such as roadsides, which makes for an unfortunately ideal chain of rest-stops for the lanternfly to chow down and spread along.
In the first years of infestations, it was theorized that the spotted lanternfly might need to feed on the tree of heaven to complete its life cycle. Although this has been disproven, researchers now know that when spotted lanternfly does not feed on tree of heaven as a nymph, it affects the insect’s ability to reproduce later on; they’re eggs hatch later, the nymphs take longer to become adults, and the adults take longer to lay their eggs.
These findings are detailed in a paper co-authored by Hoover. The relationship between the two invasive species is not as intimate as suspected, but as far as controlling the spotted lanternfly, Hoover said, “In my opinion, the best approach is killing the tree of heaven as much as you can.”
Robert Sullivan, a Horticultural Inspector for the New York DEC confirmed that when it comes to starting to search for lanternfly eggs the effort begins with inspecting any tree of heaven where there’s been a sighting, along with any other preferred hosts.
Indeed, a tree of heaven, splotched with egg masses, was nearby where the spotted lanternfly was sighted in Ithaca. Still, Inspector Sullivan, who’s looked over the Ithaca area himself, is optimistic about managing the lanternfly’s spread in Ithaca — tree of heaven or not.
“We believe it’s been here for a short period of time, probably either this year or maybe as far back as last year,” he said.
But even with this edge, scraping egg masses is just buying time. Maybe not this year or next, but with the way things look now, New York state is going to have to learn to live with the spotted lanternfly.
Learning to Live with It
The people in Southeastern Pennsylvania are familiar with the spotted lanternfly, and they can tell you it isn’t shy of people. It survives just as well in urban environments, and when late summer comes, lanternflies move in droves through the streets. While adorned with beautiful wings, the spotted lanternfly is not actually a good flyer, so people use their boots for more than walking, executing the “ lanternfly stomp” as they go.
“Yes, that is what they call it,” Heather Leach said.
Right now, insecticides are the most relied upon control method for spotted lanternfly, but the financial and environmental costs are unsustainable, nor are they wholly effective.
“Part of the problem is you treat right over here, and the next thing you know, a few months later, they’re right next door in huge numbers in an area you didn’t treat,” Penn State’s Kelli Hoover, whose current research is focused on biocontrols for the spotted lanternfly, said.
Chemical controls are going to be integral for fighting the spotted lanternfly, but they will need to be developed to target it without killing other insects in the process, or allowing excess chemicals to seep into the environment. One such idea is a wall Leach and her team built and covered with insecticide-soaked netting.
Compared to native insects, the spotted lanternfly’s natural behaviour makes it susceptible to this poisonous wall. Leach said, “You have a bug that’s very attracted to tall objects, and is very numerous.” She explained that the spotted lanternfly tends to invade the areas it feeds on. After feeding, it leaves, then reinvades from that same direction. So in the case of a vineyard or other areas of agriculture, this wall, Leach said,“…could be a really exciting way to bring that insecticide to the bug rather than treating the entire vineyard again.”
This wall is a nascent idea. Up to now, vineyards afflicted with serious lanternfly infestations have turned to spraying sometimes up to three times a day. For context, that is a hands-down ridiculous amount of insecticide needed to keep these bugs off of grapevines. Dr. Hoover said that, “…is not something you would see in any other industry.”
Versus insecticides, biocontrols or using natural enemies to reduce invasive species populations, are much less time and resource intensive for people.
Who’s Having Lanternfly for Lunch?
A biocontrol uses other living things to reduce the populations and impacts of an invasive species so, when successful, this management technique can be thought of as a matter of letting nature run its course. In some cases, a biocontrol can be a natural enemy of an invasive, coming from the same natural habitat.
Hoover said that there are two parasitoid wasps that are candidates for introduction. In its natural range, spotted lanternfly populations are kept in check by one wasp species that lays their eggs into the lanternfly’s own egg masses, and the other parasitoid wasp lays its eggs into the lanternfly nymphs. As the wasp larvae develop in their hosts, they completely consume them.
Although introducing these wasps may sound like a quick solution to cutting down spotted lanternfly populations, the process for introducing a species as a biocontrol is glacial and meticulous, taking about ten years. It requires approval from government organizations all the way up the ladder, including the International Committee on Biological Control. In the meantime, identifying native species that feed on the spotted lanternfly is where progress can be made now, and there are already some promising leads.
Hoover said that various native creatures have been observed eating the spotted lanternfly: birds, insects — even some mice and fish. Right now, these native species haven’t caught on to the abundant feast the spotted lanternfly could be for them, but Hoover and one her Ph.D. students, Anne Johnson, are looking into how they can turn hungry eyes onto these pests.
All of these creatures exhibit a common behaviour: when they nibble on the spotted lanternfly, they leave the wings behind. Hoover said that as of yet her research hasn’t confirmed it, but the wings are likely where the spotted lanternfly’s chemical defenses are stored, and any native species that becomes a part of the control program will have to show an aptitude for eating around them.
For integrating birds into a control program, Hoover described how tearing off the spotted lanternfly’s wings off, then feeding their bodies to wild birds may be a way to teach them to eat the insect. Native insect predators, however, are where Hoover gets excited. Spiders and assassin bugs never encounter the lanternfly’s chemical defenses. They have mouth parts that they use to pierce into the lanternfly’s body and suck out their insides. She said, “And we suspect that these are going to be our go-to predators.”
The hopeful strategy with these insect predators is, as Hoover said, “If we could produce these in large enough numbers, to release them, like an augmentation of what’s already present,” then these waves of assassin bugs and spiders can fight down the spotted lanternfly.
For all the promise that may come with these management strategies, their variety only encourages increasing funding, research and a sustained effort. The spotted lanternfly illustrates a pattern invasive species follow wherever they establish: if the program to eradicate them doesn’t work, then the cost and commitments necessary for dealing with them grow.
Efforts from government agencies and research programs can do the heavy lifting so businesses don’t have to face the cost of the spotted lanternfly alone, but individuals can play a key role in monitoring the spread of the spotted lanternfly. Searching for this invasive pest relies on the public to report sightings. To learn how to identify the spotted lanternfly, you can go to the DEC’s website.