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Experts foresee spotted lanternfly infestation in 2020


If you live anywhere in Southeastern Pennsylvania, chances are you’ll immediately recognize the names “spotted lanternfly” and “emerald ash borer.” The ash borer, originally discovered in Michigan in 2002, continues to decimate ash species in 2020.

The lanternfly has a more recent American history, consuming bark and fresh tree growth since its discovery in 2014. The USDA calls the spotted lanternfly “the worst invasive species the U.S. has seen in the last 150 years,” so it’s position as a major topic at this year’s Green Industry Forum came as no surprise.

Hosted by Professional Landscape Services Inc., the forum is an annual educational gathering for local tree and landscape service companies, offering talks by industry professionals, equipment displays and course credits through the Penn State Extension program. Keystone Tree Experts and Hugh Marshall Landscaping cohosted the event, with the former providing the forum’s first speaker.

Bob McMullin, an ISA Certified Arborist and founder of Keystone Tree Experts, opened with a sobering message: “For the most part, spotted lanternfly was only a minor problem last year in the general area of Doylestown and New Hope until early September when things changed rapidly. We were invaded with thousands of SLF and thousands, if not hundreds of thousands, of SLF eggs were laid that will hatch, as nymphs, in May. Adults emerge in late July or August and the war begins in earnest. We expect a major infestation in Bucks County.”

According to McMullin, that war includes the wine and fruit industries, where vineyards and orchards are two of the lanternfly’s favorite haunts. The flies consume the succulent growth of vines and fruit trees then release their excrement, called “honeydew,” all over the surrounding branches and trunk. Honeydew becomes a sooty mold that blocks the tree’s ability to photosynthesize and weakens its capacity to fight other infections.

Worried homeowners should act fast this spring to combat the invasion. One action you can take is to remove any tree-of-heaven (Ailanthus altissima) from your property. As the preferred host of SLF, this invasive tree from Southeastern Asia is the source of many outbreaks. Despite the presence of this creature comfort, the lanternfly threatens many native trees such as red and silver maple.

According to McMullin and the Pennsylvania Department of Agriculture (PDA), you should scrape egg masses into a container filled with rubbing alcohol or hand sanitizer. Egg masses are long and greyish-white and covered in a protective substance from the female. Unfortunately, they can collect at the top of trees, rendering them inaccessible to those without large trucks or ladders. Another realistic option is to band trees with sticky tape to capture nymphs, the youngest stage of SLF.

Although reports suggest that some native insects such as praying mantises, spiders, and wheel bugs feed on the lanternfly, experts encourage homeowners not to purchase them online for release into gardens or trees. Online marketplaces can lack serious vetting processes and could send new invasive species into the landscapes of Pennsylvania.

Scientists with the Pennsylvania Department of Agriculture and Penn State are researching the use of insecticides on spotted lanternfly; however, some insecticides are not recommended for use by property owners due to their high toxicity. Before you use them to combat SLF, the experts warn, know that exposure can be limited by hiring a professional applicator through a tree service.

McMullin stresses that professionals are an alternative and will protect your existing landscape, but they can’t solve the entire issue: “The purpose of treating your trees and shrubs against SLF is to reduce the damage caused by this very serious invasive insect. Total eradication of SLF on your property is impossible.”

Key to understanding a pesticide at home is reading the label, according to Maria C. Gorgo, another speaker at the Green Industry Forum and a horticulture educator with Penn State Extension. “It’s important to read the label. It’s important to follow the instructions,” she says, emphasizing the lax standards of some pesticide users. “Let’s read the label, it’s the law.”

She’s not joking for effect. FIFRA, or the Federal Insecticide, Fungicide, and Rodenticide Act, requires that all pesticides be registered with the EPA. You can find an EPA Registration Number on the label and avoid illegal pesticides that can be highly toxic to people, pets, and wildlife. Labels also provide a list of required PPE (personal protective equipment) and signal words, which supply information on the acute toxicity of a product. Signal words come in all-capital letters, including DANGER (most toxic), WARNING (moderately toxic), and CAUTION (least toxic).

No matter which method you choose, stopping the spread of the spotted lanternfly will help protect your gardens and trees. Every egg mass scraped, every nymph stuck, and every tree-of-heaven removed contributes to fighting this ravenous invader.