EXTENSION CORNER: Keep watch for Spotted Lanternfly nymphs this spring

Laura Bailey, Cornell Cooperative Extension of Yates County Natural Resources Educator & Northwest Regional Director of the Master Forest Owner (MFO) Program

Spotted lanternfly (Lycorma delicatula) is an invasive insect native to Asia. Its preferred host tree is the invasive tree-of-heaven (Ailanthus altissima), but it can also feed on and cause significant damage to a wide variety of other plants including grapevines, hops and apple, maple, and walnut trees. The first known infestation of the invasive spotted lanternfly (SLF) was discovered in New York State on Staten Island during August 2020. Soon after, additional infestations were discovered in Port Jervis, Sloatsburg, Orangeburg, and Ithaca. Currently, these are the only known infestations or populations in the state, but several individual adult SLF have previously been found in counties across the state including Yates County, in September 2018.

Identification of SLF

SLF egg masses overwinter and hatch in the spring, beginning around April and into the early summer. Nymphs emerge black with white spots, starting off very small, around the size of a tick. They will grow or transition through four different growth phases, getting larger each time, until they reach about ½ inch and turn red with white spots. Soon after they reach this final growth stage, they will begin transitioning into adults. Adults begin to appear in July and are approximately 1 inch long and ½ inch wide at rest. Their wings are grayish with dark spots and a speckled band at the rear. When they open their wings, the lower portion is red with black spots and the upper portions are dark with a white stripe. Their abdomen is black (males) or yellow with black bands (pregnant females). Egg masses are laid on nearly any flat surface, beginning around September and into November. When egg masses are first laid, they are a creamy-white, putty-like substance that quickly becomes pinkish-gray and eventually turns a darker tan to brown and becomes cracked and scaly.

Spread of SLF

SLF are plant hoppers and can jump and fly short distances to other plants and travel up to a few miles with the assistance of air currents, but their long-distance spread is facilitated largely by human activities. SLF move to new areas primarily by hitching rides on vehicles or attached to materials being transported. The most commonly moved life stage are egg masses. These are laid in the fall on vehicles, boats, firewood, rocks, outdoor furniture and other smooth, vertical surfaces. If they aren’t removed from these surfaces before travel, they have the potential to hatch in new locations and establish an infestation. Adults and nymphs can also get trapped in cars or gear and equipment such as tents and be moved to a new location and establish a population.

SLF Myths

As people deal with and worry about the impacts of SLF, they are sometimes willing to believe and try anything to control it, but it is important to make sure that any attempts at management are supported by research as safe and effective practices. Spotted Lanternfly Extension Associate at Penn State’s College of Agricultural Sciences, Heather Leach and her colleagues, debunked some of the myths that are circulating:

Pressure washing destroys spotted lanternfly eggs:  FALSE. While pressure washing might physically remove egg masses from surfaces, there is no evidence that it kills eggs. Additionally, high-pressure sprays can cause permanent damage to trees and other living plants.

* The most effective way to destroy egg masses is to scrape them off using a plastic card or putty knife. Then, place the masses into a bag or container with rubbing alcohol or hand sanitizer, which can be disposed of in the trash. They also can be smashed or burned.

Milkweed is toxic to spotted lanternfly: FALSE. According to Penn State Extension educators, milkweed leaves contain cardiac glycosides. These compounds affect heart function, making them toxic to most species of birds and mammals. However, there is no science currently showing that it is poisonous to the spotted lanternfly, Leach said.

* On a positive note, milkweed is the sole host plant of the monarch butterfly. By planting milkweed species native to their region, property owners can support this important pollinator. But they should not expect to milk any benefit related to the spotted lanternfly.

The spotted lanternfly needs tree of heaven to reproduce: FALSE. It does not, according to Kelli Hoover, professor of entomology, whose lab researched the insect’s reproduction cycle. She said while Ailanthus altissima, a noxious and invasive weed tree commonly known as tree of heaven, is the pest’s preferred host, spotted lanternfly can produce offspring without it. Interestingly, development from egg to adult was slightly faster when spotted lanternflies were given tree of heaven, suggesting that it is a good host for them. Because tree of heaven is attractive to spotted lanternfly, Hoover recommends removing it, if affordable and feasible.

Homemade sprays are safe and effective: FALSE. Folks may be tempted to use home remedies that include household items such as dish soap, glass cleaner, vinegar, salt, garlic and chili/cayenne peppers. These suggestions may have the potential to harm humans, pets and plants, do not come with precise directions, may not be effective, and their use can violate the law, noted Emelie Swackhamer, a horticulture extension educator based in Montgomery Country, one of 26 counties in the current spotted lanternfly quarantine zone. She encourages nonchemical control methods such as destroying egg masses, swatting the insects with fly swatters, trapping them and eliminating the tree of heaven. For homeowners who choose chemical control, she recommends they use a registered insecticide and research the pros and cons. It is good idea to use least toxic options first, including organic or natural-based insecticides such as neem oil or insecticidal soaps.

Spotted lanternflies are luminescent: FALSE. The origin of this fallacy most likely lies in the pest’s name, according to Julie Urban, associate research professor in the Department of Entomology. “‘Lanternfly’ is a name that refers to the insect family ‘Fulgoridae,’ to which the spotted lanternfly and more than 500 other insect species belong,” she said. “These insects often possess unusual physical features, including an extension or enlargement of the head, as in the case of spotted lanternfly.” At one time, scientists hypothesized these insects’ enlarged domes housed bioluminescent bacteria that could make them glow. This led to the insect family being named for “Fulgora,” the Roman goddess of lightning. While the spotted lanternfly possesses powers such as feasting on plants, depositing sticky honeydew and taking up residence anywhere, the ability to glow — or to fly well, for that matter — is not among them.

What To Do if You Find SLF?

If you believe you have found SLF in NY take pictures of the insect, egg masses, and/or signs of infestation (include something for scale such as a ruler, coin, or your hand if possible) and record your location. Email the information to spottedlanternfly@agriculture.ny.gov.

For additional questions about SLF and tree-of-heaven, contact CCE Yates Natural Resources Educator, Laura Bailey at lb698@cornell.edu or 315-536-5123.

Spotted Lanternfly nymphs and adults.