Protection from Spotted Lanternfly
Question: In January 2018, a new invasive pest, the Spotted Lanternfly (SLF), was first seen in Northern Virginia. Is this insect a problem and what do I need to know to protect my property?
The Spotted Lanternfly (Lycorma delicatula), was discovered in the U.S. in 2014 in southeastern Pennsylvania. Native to Asia (China, Japan, Korea, Vietnam, and India), the SLF probably arrived in the U.S. in materials shipped from Asia. As of April 2021, SLF is found in Pennsylvania, New Jersey, Virginia, West Virginia, Maryland, Connecticut, Delaware, New York, and Ohio.
SLF has been detected on over 70 different host plants. It is considered a serious pest of some commercial crops, such as hops, grapes, apples, peaches, other orchard fruit trees, logging, tree- and wood products and green industries. It can also be a nuisance to homeowners if present in large numbers, damaging ornamental plants, including trees and shrubs. SLF is most commonly found on Tree-of-heaven (Ailanthus altissima), an invasive species that is widespread throughout Virginia. SLF is also present on black walnut, red and silver maples, Virginia creeper and oaks. The economic impact could total in the hundreds of millions of dollars for those in grapes, apples, hops, and hardwood industries. In April 2021, the Delaware Valley Journal reported that the SLF could cost Pennsylvania commercial agriculture $324 million annually.
Identifying the Spotted Lanternfly
SLF is a planthopper, not a fly as its name implies, and it sucks sap from the vascular tissue (phloem) of the trunk, stems and leaves of plants. It was named lanternfly because scientists mistakenly thought these insects glowed in the dark like fireflies.
Knowing the life cycle of the SLF and when each life stage occurs can help with identification:
- September to November – the adult female lays her eggs in masses (1-1.5” long and ½-3/4” wide) which look somewhat like splashes of gray-brown mud with a waxy coating.
- April to June – the early-stage nymphs are wingless, black with white spots and approximately 3/8” long after the 3rd molt; they move quickly and may dart around the stem or under the leaf.
- June to July – the late stage nymphs are approximately 7/8” long and are now red in color with black and white markings; they can quickly jump or hop away.
- July – after molting, the exoskeleton can remain on the plant for some time (the same way a cicada will leave behind its exoskeleton).
- mid-July to October – the adult SLF is approximately 1” long with a wingspan of 1.5”; its front wings are light brown/grey with black spots and wing tips with thin broken black lines outlined in grey; the hind wings have contrasting patches of red and black with a white band; the legs and head are black; the abdomen is yellow with broad black bands.
Where to Look for SLF & Signs of Damage
Damage may appear as oozing sap, wilting, leaf curling, yellow or brown leaves, leaf loss or production of honeydew, a sugary liquid waste product of the SLF with a vinegary smell. The honeydew can cover lower branches, the trunk, and/or on vegetation under the tree. This sweet liquid attracts sugar-loving ants, flies, bees, and wasps and encourages the development of sooty mold (a black fungus that blocks the photosynthesis of the plants covered by it). The sap can also lead to white yeast and mold growth.
- April to July – check small stems and undersides of leaves of trees (tree of heaven, and other trees and vines mentioned above) for early and late-stage nymphs.
- July to November – search for the adult SLF and the damage that may have been done to trees and plants.
- October – look for multiple egg masses on trees and other plants, stones, grills, lawn furniture, rusty metal.
How to Control the Spread of SLF
- Familiarize yourself with the life cycle of the SLF, learn how to identify it and report any sightings of this pest to your local Cooperative Extension office.
- If you have seen SLF on your property, use best management practices to stop the spread: remove SLF egg masses, nymphs and adults and follow guidelines for proper application and timing of organic or biological controls. Avoid insecticides, if possible.
- If you live in an area where there is a quarantine, follow the follow the guidelines for mitigating the spread of the pest.
- Search and destroy the primary host for the SLF –any tree of heaven growing on your property (seedlings or larger trees) using appropriate treatments from this Blue Ridge Prism alert.
The damage can be devastating, but there is some slightly better news about SLF:
- It does not bite.
- It does not sting.
- It does not overwinter inside houses or cause harm to the house.
- While egg masses can overwinter, the adult SLF does not survive Virginia winters.
- It is safe to eat plants fed on by SLF.
To learn more, visit the Virginia Cooperative Extension web page for a short video on the Spotted Lanternfly, the Virginia Department of Agriculture and Consumer Services (VDACS) web page, and the resources listed below.
“Five Things to Know about the Spotted Lanternfly,” Artika Casini, University of Delaware, UDaily, 18 Aug. 2020.
“Now is the Time to Tackle Tree of Heaven,” Piedmont Master Gardeners, Timely Topics, 15 Sept. 2020.
“Pest Alert: Spotted Lanternfly, Lycorma Delicatula,” Eric Day et. al, Virginia Cooperative Extension, Publication, ENTO-265NP, 2018.
“Spotted Lanternfly,” Eric Day et. al, Virginia Cooperative Extension, Publication, ENTO-180NP, 1 Jul 2018.
“Possible Spotted Lanternfly Look-Alikes,” Theresa Dellinger & Eric Day, Virginia Tech, Department of Entomology, Publication, ENTO-276NP, 2018.
“Spotted Lanternfly Management in Vineyards,” Dave Biddinger et. al, PennState University, PennState Extension, Updated 20 Apr. 2021.