I recently attended a workshop focused on early detection of Spotted Lanternfly (Lycorma delicatula) (SLF) in Fairfax County. Speakers represented the Virginia Cooperative Extension, the Virginia Department of Forestry, and the Fairfax County Urban Forest Management Division.
Spotted Lanternfly is native to China, and has also been found in India, Vietnam, and Japan. Introduced in Korea in 2006, it is considered a pest in that country. The insect was first detected in the US in September 2014, in Berks Country, Pennsylvania, where it was likely imported as egg masses laid on landscaping stone. The first Virginia populations were detected in the Winchester area last year.
A hemipteran insect, L. delicatula is highly invasive and can expand its range rapidly; it can use at least 70 North American host species, although it has a particular association with Tree of Heaven (Ailanthus altissima). A phloem feeder, the lanternfly sucks sap from its host plant, leading to wilting and reduced photosynthesis. Spotted Lanternfly also exudes honeydew, which promotes the growth of sooty mold, further impairing the health of its host plant.
Because its American hosts include species of grapes, hops, stone fruits, and Malus, the threat of significant economic losses looms.
Egg masses are laid on the roughened, brocaded bark of A. altissima, other tree species, and even weathered stone, concrete, and metal. Spotted Lanternfly undergoes incomplete metamorphosis, the eggs hatching into nymphs that go through several instars before transforming into winged adults. It is conjectured the lanternfly extracts and isolates toxins from its ailanthus host, and hence that the bright red coloration of its later instars and adults constitutes aposematic coloration. The adult, about an inch long, resembles a colorful black-brown-and-red moth.
In Virginia, first instar nymphs for this season were observed on April 26, 2019. If you see an egg mass, nymph, or adult that you suspect to be Spotted Lanternfly, please report it to the Virginia Cooperative Extension at https://ext.vt.edu/spotted-
Here in Fairfax County, foresters hope to monitor possible sites where Spotted Lanternfly might first appear, and that means monitoring populations of A. altissima, itself a non-native invasive plant species. To recap field identification of this plant, look for compound leaves with 11 to 41 leaflets; each leaflet bears a small “thumb” with glands. Yellowish flowers are borne in panicles; the fruits are yellowish or brown samaras. Twigs are stout and hairless; leaf scars are large and triangular, with numerous bundle scars. When crushed, the plant produces an odor (in the words of Jim McGlone) “of burnt peanut butter.”
It turns out that our map of ailanthus patches in Fairfax county is incomplete, especially on private property. Therefore, please report any Fairfax County observations of Tree of Heaven (Ailanthus altissima) to MAEDN (Mid-Atlantic Early Detection Network), via the MAEDN mobile app or web site.
By David Gorsline, VNPS Potowmack Chapter Membership Chair and Virginia Master Naturalist
This article also appeared in the Summer, 2019 edition of the Potowmack News.
Editor’s Note: Additional resources about Spotted Lanternfly: