Brian Eshenaur, Cornell University’s integrated pest management associate director, is grateful to the research community for providing New York State with a heads up about the spotted lanternfly (SLF) in 2014. Due to the warning and New York’s slow-the-spread strategy, the state successfully delayed the introduction of this invasive pest until 2020 when it was first detected on Staten Island.
It’s likely that the SLF was in New York prior to 2020, but the insect is very cryptic and difficult to detect at low levels, said Chris Logue.
Logue is director of the Division of Plant Industry with the NYS Department of Ag & Markets. He and Eshenaur provided an update on the SLF during an August webinar.
“I don’t believe any crop losses have occurred in New York State due to spotted lanternfly. I think because we got the warning from Pennsylvania and our partners at Penn State,” said Eshenaur.
Fears that SLF would impact New York’s ag industries have so far not come to fruition. Growers and researchers are concerned that the pest might impact the grape industry and are monitoring the situation in grape-producing areas across the state. However, at this point other crops such as commercial vegetables, maple syrup-producing trees and hay and grain crops do not appear to be threatened.
“That’s not to say that a particular producer couldn’t run into a problem with spotted lanternfly at some point in the future,” cautioned Logue.
SLF, an invasive insect native to Asia, was first detected in North America in Berks County, PA, in 2014. It has “fly” in its name, but it’s actually a plant hopper. As juveniles, they spread by hopping, and as adults by flying short distances.
The SLF uses its piercing-sucking mouthpart to feed on sap from over 100 different plant species including economically important ones like grapevines and maple, black walnut, birch, willow and other trees. The feeding damage can significantly stress certain plants like grapevines, which can lead to decreased health and potentially death.
Additionally, when SLFs feed on plants, they leave behind a sticky residue called honeydew. This substance attracts other insects and causes mold growth.
The SLF is highly attracted to the tree-of-heaven (Ailanthus altissima), but according to Eshenaur and Logue, it’s a highly debated topic among researchers whether removing the tree-of-heaven will reduce SLF populations.
Currently, SLF has been confirmed in 29 New York counties and 19 states, primarily in the Northeast and Mid-Atlantic. New York requests that all counties report SLF sightings (excluding counties where they have known large populations: Dutchess, Nassau, New York City counties, Orange, Putnam, Rockland, Suffolk, Sullivan, Ulster and Westchester).
Continued vigilance and detection are important because SLFs are often “hitchhikers.” Adults lay their eggs in autumn on all types of materials including metal, firewood, pallets, lawn furniture and automobiles. When these items are moved, the egg masses, which look like dirt or a muddy material, can be transported to new areas. Each egg mass contains 30 – 50 eggs, and they can survive sub-zero temperatures.
Spotted lanternfly adults covering egg masses on a tree in autumn. Photo courtesy of NYS IPM
“So, you could have an instant population from egg masses in a new area. We know that this has occurred nationally where a farm moved equipment across a couple states and a new population popped up there,” said Eshenaur.
The adults are also good hitchhikers, frequently getting caught up in different modes of transportation such as the wheel wells of cars, in the vents along windshields and at the intake for climate control systems.
Trapping is one current management strategy for eradicating SLF. There are no known baits to lure the insects, so the traps rely on the habit of the insects to climb up trees where they are caught in traps that look like reverse funnels.
Placing sticky traps around trees is another management strategy. Eshenaur advised placing a screen over the sticky traps to avoid catching insect-feeding birds such as woodpeckers. Commercial sticky traps are available for purchase.
Some municipalities have even used vacuum removal on street trees, and homeowners have deployed Shop-Vacs. Pesticides can be challenging to use for SLF because they must be able to reach the tree canopy. Regarding the use of pesticides, Eshenaur said, “We’re going to recommend if you’re really concerned, consult an arborist.”
Researchers are also studying specific fungi that naturally feed on SLF that could be cultivated and released into the environment as a treatment. This method is an example of biocontrol. There is also some research looking at predators imported from areas where the pest is native which could be released into infested areas.
While SLFs don’t bite or sting humans, they can be a nuisance and continue to pose an economic threat to crops and agritourism enterprises. People sitting down to enjoy a glass of wine at a Finger Lakes winery would likely be unimpressed to see large numbers of SLF adults. Commercial honeybee hives leaving New York State now need to be inspected before being shipped to California for almond pollination.
New York encourages continued monitoring and awareness for the SLF as researchers continue to develop strategies to monitor and control this novel pest. The more they learn, the more questions Eshenaur and Logue have.
“We’re constantly learning about spotted lanternfly. There are a lot of basic questions that continue to need answers, and it will be a long time developing and having confidence in those answers,” Logue said.
by Sonja Heyck-Merlin
