Keep watch for Spotted Lanternfly adults and egg masses
FINGER LAKES – 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.
What risk does SLF pose to N.Y.?
SLF poses a significant threat to New York’s forests and agriculture. Damage and stress caused to host plants, including grapevines and apple trees, could impact fruit yield and lead to economic losses. New York’s annual yield of grapes and apples has a combined value $358.4 million. In addition to plant damage, honeydew excreted by dense populations of SLF could also hinder resident and tourist outdoor recreational activities and associated economic revenues.
Damage caused by SLF – Nymphs and adults suck sap from stems and leaves, stressing the plant and making them more vulnerable to disease and attacks from other insects. As they feed, SLF excrete a sticky substance known as honeydew, which attracts sooty molds that interfere with photosynthesis, affecting growth and fruit yields. SLF may also change plant species as it goes through its different developmental stages throughout the year. The nymphs tend to feed on a larger variety of plants, while adults prefer to feed and lay eggs on the tree-of-heaven.
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 can begin to appear as early as 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.
This invasive tree species was introduced to the U.S. in the late 1700s as a street and landscaping tree. It has since become an invasive tree in urban, agricultural and forested areas throughout New York and much of the U.S. Its compound leaves look similar to staghorn sumac and walnut trees, which are also host trees for SLF, but some of its defining features are:
• Bark is smooth and green when young, eventually turning light brown to gray, resembling the skin of a cantaloupe.
• Leaves have a central stem in which leaflets are attached on each side and range in length from 1 to 4 feet with anywhere from 10 to 40 leaflets. At the base of each leaflet are 1 to 2 protruding bumps called glandular teeth, which is a very specific identifying feature to tree-of-heaven. When crushed, the leaves and all plant parts may give off a strong, offensive odor, compared to the smell of rancid peanut butter.
• Seeds on female trees are 1- to 2-inch twisted samaras, or wings. The samaras are found in large clusters. They are mauve colored in late summer and fall and often persist on the tree throughout winter.
What can you do?
Familiarize yourself with the signs of a SLF infestation and learn how to identify the insect in its various stages of development. Inspect trees, outdoor furniture, vehicles, boats, firewood and other smooth vertical surfaces for egg masses, especially if travelling from an area with a known infestation. Also learn how to identify, inspect and manage tree-of-heaven. Some additional proactive measures you can practice include:
• Rake up and dispose of tree-of-heaven seeds to prevent the growth of additional trees
• Dig or pull tree-of-heaven saplings, making sure to remove the entire root system
• Consult with a tree professional on proper management and herbicide use to effectively manage large tree-of-heaven. Cutting down a mature trees leads to prolific basal sprouting and root suckering, which requires repeat efforts over many years to lead to eradication of the tree. Relying on cutting alone to remove the tree is impractical and ineffective.
• The State has set up a monitoring platform for volunteers to survey a specific area, or grid, of land on iMapInvasives and enter data from their survey work. Sign up for a grid at https://www.nyimapinvasives.org/slf
What to do if you find SLF?
If you believe you have found SLF in New York, 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 firstname.lastname@example.org. There is also a Public Report Form available at https://agriculture.ny.gov/spottedlanternfly. For additional questions about SLF and tree-of-heaven, contact CCE Yates Natural Resources Educator, Laura Bailey at email@example.com or 315-536-5123.