Until recently, we’d been lucky enough in New Jersey to have escaped the expanding range of spotted lanternfly infestations. But all that has changed.
On July 31, 2018, the NJ Department of Agriculture confirmed that the spotted lanternfly had been found in northern Mercer County, as well as in Warren County earlier in the summer. As a result, Mercer, Warren and Hunterdon counties are now under quarantine.
In Pennsylvania, all of Bucks County is under quarantine, as are Berks, Carbon, Chester, Delaware, Lancaster, Lebanon, Lehigh, Monroe, Montgomery, Northampton, Philadelphia, and Schuylkill counties.
If you are moving any of the articles on this list out of those counties, you’ll need to check carefully for spotted lanternfly and certify that you have done so.
What Is The Spotted Lanternfly?
Spotted lanternfly (SLF), Lycorma delicatula, is an invasive planthopper native to Southeast Asia. It was first discovered in Berks County, Pennsylvania in 2014 and has since spread to neighboring counties and states.
The pest gets its name from spots that decorate its back and wings, and is quite attractive with its wings spread to show vivid red, black and white areas.
But make no mistake about it – this insect wreaks havoc wherever it goes.
Spotted Lanternfly Damage in New Jersey & Pennsylvania
The spotted lanternfly feeds on woody plants, sucking out sap and leaving behind honeydew, a sticky, sugary liquid that encourages the growth of black sooty mold on any surfaces it covers. While sooty mold is harmless to people, it can damage plants (and it’s rather unsightly).
SLF feeding also damages the tree or plant, resulting in oozing sap running down the trunk, wilting, leaf curling and even plant death. It also destroys fruit from that plant, partially through direct damage and partially by covering it with sooty mold, making it unappetizing and not suitable for commercial use. Apples from apple trees, grapes from vineyards, and hops for making beer are just some examples of fruit that has been ruined by this pest. In Pennsylvania alone, authorities estimate that $18 billion worth of agricultural commodities are at risk of destruction from the spotted lanternfly.
The spotted lanternfly is most commonly found on the Tree of Heaven (Ailanthus altissima), but over 70 varieties of woody plants can be damaged by SLF at any stage of development. For example, it’s known to feed on many common shade trees, such as red and sugar maples, chestnut oaks, tuliptrees and American sycamores.
Aside from the damage to trees and agricultural crops, SLF tends to congregate in hoards (often around Ailanthus trees) that cover everything in sight, making it unpleasant to be outdoors – especially when adults take to the skies in swarms as part of the mating process.
The insect is toxic if consumed (so keep your pets away from it!) and has no natural predators here in the USA.
What To Look For
The spotted lanternfly has 4 stages of development: eggs, two nymph stages and adult.
SLF egg masses appear shiny and grayish brown (somewhat like a smear of mud), making them difficult to see if they’re on a tree. Eggs can be present from late September through May.
Egg masses can be left on nearly any surface, including logs, outdoor, camping and recreational equipment, and cars or trailers that are then transported to other areas and states, which is one way that the pest has spread to other areas.
After eggs hatch (starting in April), the SLF goes through several stages (called nymphs) before reaching maturity. These nymphs are present from late April through mid-October. They’re small (1/4 to ½ inch) but quite capable of inflicting damage on host plants and hitching a ride to new feeding grounds.
Adults are around 1 inch long and can be seen from late July through mid-December. They’re often seen in large groups
Black sooty mold or sticky areas on a plant or tree are good indicators of SLF feeding. However, other pests can also cause similar symptoms, such as aphids, leafhoppers, planthoppers and scale insects.
You may also see an increase in wasps, bees, ants, and hornets that are attracted to the weeping wounds left by SLF.
If you see these signs on your tree and aren’t sure what’s causing it, give us a call and one of our Tree Experts will inspect it and give you a diagnosis.
Management of Spotted Lanternfly
The spotted lanternfly is highly mobile; there’s no way to keep it off your property. It’s just a matter of time before you find one (or many!).
There are two ways to control the spread and amount of damage caused by SLF –
- preventive treatments (such as removing egg masses) and
- directly targeting the nymphs and adults with a variety of insecticides.
Preventive Treatments for Spotted Lanternfly
Prevention focuses on two things – preventing eggs from hatching and preventing nymphs from reaching the tree canopy where they feed.
One option is to manually remove egg masses by scraping them off surfaces and destroying them (such as by immersing them in rubbing alcohol, bleach or hand sanitizer – just leaving them on the ground won’t kill them). You can also place them in a sealed plastic bag and dispose of them. You’ll usually find egg masses between September and June.
The problem with this is that egg masses can be high up in the trees where you can’t reach them, they’re hard to see, and they can be on just about any surface, including under your car! Plus, even if you eliminated all egg masses on your own property, new lanternflies will come in from neighboring properties.
To prevent nymphs from climbing tree trunks, you can place a sticky band around the trunk to trap them as they climb. You can buy bands specifically for this purpose or wrap your trees with duct tape (sticky side out). Bands should be in place in early spring to catch newly emerging nymphs – it’s not effective against flying adults.
Because the Tree of Heaven is the preferred host for SLF, preemptively removing all (or most – see below) of these trees on your property can significantly cut down on the number of pests. Tree of Heaven can reach 100 feet tall and must be treated with herbicide before being cut down; it’s best to call in a tree care professional for the job. Trees should be removed between July and September.
Chemical & Biological Treatments for Spotted Lanternfly
Experts are still investigating the best means of controlling SLF. At the moment, the US Department of Agriculture is using the systemic insecticide dinotefuran (a neonicotinoid) as an injection or bark spray to kill SLF. Both methods appear to work well but can only be applied by a tree care professional.
The organic pesticide azadirachtin has also shown promise when used as a foliar spray. However, it only works when the pest comes into direct contact with it so it’s best to bring in a professional who has the spray equipment necessary to get full coverage of all trees on your property.
One method that’s gaining attention is to use trap trees. By removing all but a few of the most attractive (to SLF) male Trees of Heaven on a property, the pest is forced to feed on the remaining trees. These can then be treated with a systemic insecticide that kills all SLF who feed on the trap trees. Although the pesticides known to be effective against SLF are toxic and non-selective (they kill other insects too, including beneficial insects and pollinators), using trap trees reduces the total amount of insecticide used in comparison to other approaches. For best results, apply the insecticide in June through August.
If You Find Spotted Lanternfly
Efforts are underway to quarantine and contain SLF before it spreads and does more damage. Here’s what to do in Pennsylvania and New Jersey.
Anyone who finds the insects or egg masses outside quarantined areas should report sightings to firstname.lastname@example.org. Include photos, if possible, to help confirm the sighting. Suspect specimens can be submitted to the department’s headquarters in Harrisburg or to any of its six regional offices. Specimens in isopropanol or rubbing alcohol can be submitted to county Penn State Extension offices. You may also call the Invasive Species Report Line at 1-866-253-7189. Please provide details, including the location of the sighting, and your contact information. Calls may not be returned immediately, as call volume is high.
In New Jersey
Specimens of any life stage can be turned in to the New Jersey Department of Agriculture’s lab for verification (make sure it’s dead before transporting it). If possible, take a photograph of the pest at any life stage (including egg masses). The photo can be submitted to SLFemail@example.com. If you can’t take a specimen or photograph, call the New Jersey Spotted Lanternfly Hotline at 1-833-223-2840 (BADBUG0) and leave a message detailing your sighting and contact information.
And don't forget that you can call on us for a spotted lanternfly inspection, treatment suggestions and Tree of Heaven removal.