With spring and the accompanying emergence of insects upon us, grape growers, orchardists, nursery operators, homeowners and others in southeastern Pennsylvania are bracing for infestations of spotted lanternfly, an invasive pest from Asia that appeared for the first time in the United States in Berks County nearly four years ago.
Potentially at stake are Pennsylvania's grape, tree-fruit, hardwood and nursery industries, which generate agricultural crops and forest products worth nearly $18 billion annually. The insect also can cause damage to high-value ornamentals in home landscapes and can affect quality of life for residents.
After the lanternfly's discovery in 2014, the state Department of Agriculture imposed a quarantine regulating the movement of plants, plant-based materials and outdoor household items out of the quarantine area. Originally covering parts of eastern Berks County, the quarantine now encompasses all of Berks, Bucks, Chester, Lehigh, Montgomery, Northampton, Carbon, Delaware, Lancaster, Lebanon, Monroe, Philadelphia and Schuylkill counties.
Penn State Extension educators and College of Agricultural Sciencesresearchers are working with state and federal agriculture officials to study the insect, develop control strategies, and educate local leaders, growers and the public about what to do if they find spotted lanternflies or their eggs. The goal is to stop the pest's spread and, ultimately, to eradicate it.
Emelie Swackhamer, Penn State Extension horticulture educator based in Montgomery County, her Northampton County-based extension colleague Amy Korman, and other Penn State specialists have spoken at scores of public meetings and industry workshops, authored articles and fact sheets, served as expert sources for news media stories, trained Penn State Master Gardeners and other volunteers, and testified at General Assembly committee hearings.
Swackhamer said enlisting the public to help control lanternfly populations is a top priority. "This is a community problem, and it's going to take a community effort to solve it," she said.
Part of that effort is ensuring that citizens and businesses don't unwittingly carry lanternflies or their eggs to other areas. "Spotted lanternflies are great hitchhikers, and they will lay eggs on a multitude of outdoor objects, such as cars, RVs and campers, plant materials, and other items that could be transported out of the quarantine area," Swackhamer said. "To raise awareness, the state Department of Agriculture is using the slogan, 'Look before you leave,' emphasizing the need to inspect vehicles and other items before traveling out of a quarantined county."
Lanternfly eggs are expected to hatch in late April or early May, so knowing what egg masses look like and destroying any that are found is an important control tactic, she said. But as eggs hatch, what can a grower or homeowner do to combat an infestation?
"When I get calls from residents seeking advice, I talk them through an integrated pest management (IPM) thought process," Swackhamer said. "Start with mechanical approaches, such as scraping and destroying egg masses and swatting or vacuuming nymphs and adults, if practical. If you kill one female that could lay 100 eggs in its lifetime, you can have an impact on next year's population."
She also recommends conserving natural enemies such as spiders and praying mantids that prey on lanternflies. "If someone wants to use pesticides, they can try least-toxic options first, and they must take timing into account — not all methods will work on all life stages of the insect."
The pest does not attack fruit or foliage. Rather, it uses its piercing-sucking mouthparts to feed on the woody parts of plants, such as grape vines and the trunks and branches of trees, where it excretes a substance known as honeydew and inflicts wounds that weep with sap.
The honeydew and sap can attract bees and other insects and provide a medium for growth of fungi, such as sooty mold, which covers leaf surfaces and can stunt growth. Plants with heavy infestations may not survive.
The role of Penn State agricultural researchers and extension educators — as part of the University's land-grant partnership with federal, state and county governments — is to bring science-based information to bear in solving emerging issues such as the spotted lanternfly. With a pest that is new to North America, these efforts must start at square one.
"The spotted lanternfly is a fascinating insect," said Korman, who is an entomologist by training. "Everything we learn about it is a new discovery. But the novelty also makes it frustrating, because we don't yet know enough about it to provide all the answers people are seeking."
To develop near-term solutions for managing lanternfly infestations, Korman and Swackhamer have done applied research to test the efficacy of various pesticides, both contact insecticides and systemic products that are applied to plants and kill the pests when they feed on the sap. They also have looked at "softer," lower-toxicity products.
"What we've found so far is that these insects are not difficult to kill, but we need to conduct more tests before we're comfortable giving formal, research-based recommendations," Swackhamer said.
Researchers at Penn State's Fruit Research and Extension Center in Biglerville, Adams County, also have conducted pesticide efficacy trials with an eye toward providing control solutions for growers of grapes and apples.
Until research bears more fruit, Penn State Extension and Penn State's Department of Entomology are deploying state and federal funds to add staff and enhance extension programming. Entomologists also are seeking additional USDA grants to continue research on spotted lanternfly biology and behavior, the development of biocontrols such as natural enemies, and other topics related to this exotic and unusual pest.
As the battle against spotted lanternfly rages on, Korman urges homeowners and others not to let the "good-idea fairy" persuade them to use unconventional — and perhaps illegal — control methods that may be hazardous to themselves or harmful to the environment.
"Our goal is to provide research-based recommendations, deliver IPM solutions and promote pesticide safety, and people can draw on Penn State Extension resources to help them address these issues," she said.
For more information about how to identify and control spotted lanternfly, how to report an infestation and how to comply with quarantine regulations, visit the Penn State Extension website at https://extension.psu.edu/spotted-lanternfly or the Pennsylvania Department of Agriculture website at http://agriculture.pa.gov.