Spotted Lanternfly: a New and Unwelcome Invader

Spotted lanternfly winged adult and fourth instar nymph. Photo by Stephen Ausmus/USDA-ARS.

By Jennifer Lerner, Resource Educator, Cornell Cooperative Extension of Putnam County.

A version of this article first appeared in Cornell Cooperative Extension of Putnam County’s newsletter.

One of the most recent invasive arrivals to make its presence known in the Northeast is the spotted lanternfly (SLF, Latin name Lycorma delicatula), a colorful insect in the planthopper family that congregates in large numbers to feed on the sap of trees.

As SLF feeds, it excretes honeydew, a pleasant-sounding name for what is essentially a sticky excrement. That honeydew sometimes alerts people to the presence of the pest.

The honeydew may seem to be purely a nuisance, but the strain placed on the trees by the insects’ feeding can seriously damage the plant.

SLF’s preferred host, tree of heaven (Ailanthus altissima), is itself an unwanted invader despite its flattering moniker. While this may seem to cast SLF as an unlikely hero, the pest boasts a diverse palate that also poses a threat to many desirable crops.

Economic and Ecological Concerns

Like the brown marmorated stink bug—another problematic invader whose insatiable appetite has thrust it into the spotlight in recent years—SLF afflicts some important agricultural crops.

It feeds on—and harms—many fruit-producing plants, including apples, peaches, and grapes, along with approximately 70 others. Grape, in particular, seems to be an especially attractive host for these pests, with many growers seeing damage and trying to manage their populations.

There are ecological considerations in addition to the direct economic impacts, given that many of the affected trees and shrubs have relatives in our native ecosystem.

For example, shadblow or serviceberry (genus Amelanchier) is a close relative of the apple. It provides important forage for migratory birds who return to their nesting sites expecting to find its nutritious early fruits. Their loss would trigger far-reaching ripple effects in our ecosystem.

Although we can begin to conceive of the secondary and tertiary effects of the SLF threat, the full scope remains unclear. We simply don’t yet know how many host plants this insect can survive on or how widespread its impact will be.

How You Can Help

Remain vigilant and report any observations. Learn to recognize the insect itself as well as the signs of its presence.

While SLF may stand out because of its signature colors and spots, its egg masses are less distinctive. They are tan to light gray, laid in rows and sometimes covered with a mud-like protective layer.

If you find SLF or its egg masses, please report the sighting to your state authorities. Visit neipmc.org/go/slfqri for a compilation of state-by-state reporting instructions that will be updated as states refine their SLF strategy.

Digital photos or dead insects may also prove helpful. Honeydew may indicate the presence of SLF, but many other insects also excrete honeydew in quantities sufficient to make cars, fences, and deck surfaces feel tacky, so that alone may not be a determining factor.

People Can Unintentionally Help Spread SLF

Although adult SLF may hitch a ride on a boat, trailer, or vehicle, their egg masses pose the most insidious threat because the female can lay them on just about any surface. The New York State IPM Program provides a video of a female laying eggs at neipmc.org/go/nyslf.

Hitchhiking egg masses can be found on pallets, stone, firewood, and outdoor furniture.

People are urged not to take firewood from home to a favorite campground or weekend retreat, and similarly, not to pick up wood from far away and bring it home, as there may be a hitchhiking invader.

Inspect boats and trailers for egg masses. If purchasing used outdoor furniture, or items frequently stored outside like garden tools and wheelbarrows, check all surfaces for egg masses.

The adult insects can fly, but they spread much more quickly when humans unwittingly help them along.

How They Got Here and Where They’ve Spread

SLF is native to China, India, and Vietnam. After the insect was introduced into South Korea, it spread throughout the country—approximately the size of Pennsylvania—in only three years.

The initial U.S. infestation was found in Berks County, Pennsylvania, in 2014, and is thought to have arrived on a 2012 stone shipment.

Currently, the insect is found in 14 counties in southeastern Pennsylvania, nine counties in New Jersey, one county in Delaware, and one county in northern Virginia. While individuals have been found in other northeastern states including Maryland, New York, Massachusetts, and Connecticut, most were thought to be hitchhikers, with no confirmed populations in these states.

The New York State IPM Program maintains a frequently updated map of known SLF locations at neipmc.org/go/nyslf.

But sustained vigilance and broad public awareness will be key to limiting the spread of SLF as researchers, extension workers, and policymakers develop and implement methods and plans for neutralizing the threat.

Read more on the USDA’s SLF web page: neipmc.org/go/yjXT.

Sources

New York State Department of Environmental Conservation: www.dec.ny.gov/animals/113303.html

New York State Integrated Pest Management Program: neipmc.org/go/nyslf

Penn State Extension: extension.psu.edu/spotted-lanternfly