Spotted lanternfly, a threat to vineyards and fruit farms, getting closer to the North Fork

The Cornell Cooperative Extension of Suffolk County has issued an alert after a spotted lanternfly was identified near MacArthur Airport in Ronkonkoma, about 45 miles from Southold.

The state department of agriculture and markets issued a report of the invasive planthopper in late September, according to Daniel Gilrein, an entomologist at The Cornell Cooperative Extension of Suffolk County. The cooperative extension posted a Facebook alert on Nov. 2, noting that the state “is determining the boundaries of the population.”

The spotted lanternfly — first found in the United States in Berks County, Pa. in 2014 — was identified in western Suffolk County in September. The insect, although not dangerous to people, feeds on plant sap and may pose a threat to fruit farms. 

In large numbers, the insect has been known to kill grape vines, although most other plants appear to be less severely affected, according to Mr. Gilrein.

“The insect is not dangerous to humans or animals [and] doesn’t bite or establish populations indoors, though high numbers in landscapes and gardens can be annoying,” he said via email. “They deposit honeydew as they feed that can attract other insects and leaves a sticky residue on surfaces below that turns black with growth of sooty mold.”

He noted that spotted lantern flies prefer tree-of-heaven, a weedy invasive tree that’s common on eastern Long Island. The insects also prefer red and silver maples, hops, walnut and sumac, he said, but they’ll feed on other trees, shrubs and non-woody plants, with the exception of conifers.   

“The greatest threat from spotted lanternfly appears to be to grapes; vineyard managers on eastern Long Island are [as] well-informed, watchful and prepared as possible,” he said. “Large numbers of the insects on landscape plants will be annoying to people. There are also concerns for spread to new areas through eggs laid on vehicles, pallets and other objects, or adults that fly into cargo holds.”

Faruque Zaman, another entomologist at the cooperative extension, emphasized that information is still evolving “almost every day.” As of May 2021, the insect was reported to feed on at least 103 different plant species, he said. 

Mr. Zaman noted the insect is concerning for tree fruit growers, especially apple growers, on the East End. 

“Neither the adults or immatures are reported to directly feed on fruits but large numbers of insects feeding on the limbs and branches can affect fruit quality and reduce production,” he said, adding that other fruit tree hosts include plum, cherry, peach and apricot.

Mr. Gilrein said the Cornell Cooperative Extension of Suffolk County has been communicating regularly with local growers. 

Farms can hand-remove or destroy egg masses in the late fall through early spring, using insecticides as a last resort, he said, adding that “there may be some other ways [to mitigate impact], such as treating favored host trees in the area to control populations before they move into the vineyard.”

The insects are “very susceptible to some insecticides” and researchers are searching for natural enemies for biological control, according to Mr. Gilrein.

“Grape growers should be concerned – as they already are – given the reputation and observations of lanternflies from Pennsylvania and elsewhere,” he said. “The insects can also be [an] annoyance to workers and U-Pick visitors in orchards though apparently they don’t tend to stay feeding on trees in the orchard for long periods as they do in vineyards.”

Mr. Zaman said CCE-Suffolk has a plan for on-farm monitoring of the spotted lanternfly in vineyards and fruit orchards, including using circle traps around tree trunks to intercept young insects. “We hope more efficient monitoring tools such as a pheromone-based attractant will be developed [in the] near future and we will be able to give weekly population updates to the growers,” he added. 

The spotted lanternfly is expected to gradually become more common on the East End in coming years, although early detection and reporting can help slow the spread, according to Mr. Gilrein. 

Residents outside New York City can report sightings online or email [email protected]v. The Cornell Cooperative Extension of Suffolk County offers educational resources online as well.