Despite targeted eradication efforts, infestations of spotted lanternfly continue to spread to more counties in Pennsylvania, New Jersey, and nearby states, threatening a variety of crop-bearing and hardwood trees.
Some 26 counties in five states have declared quarantine zones as of Nov. 12, up from 17 counties at this time last year. An additional 27 counties in eight states have reported sightings of the invasive pest, compared with 23 counties last year, according to the New York State Integrated Pest Management Program at Cornell University.
(photo above of spotted lanternfly: Cornell Cooperative Extension)
“If allowed to spread in the United States, this pest could seriously impact the country’s grape, orchard, and logging industries,” the USDA has warned. The department has dedicated $20 million of emergency funding since last year to impede its spread.
Damage to apples is a major concern in areas at risk from spotted lanternfly infestations. This map shows apple planted areas in states where the invasive pest has established itself or there are fears it could spread.
The spotted lanternfly (Lycorma delicatula) is an insect native to southern Asia that was accidentally introduced to North America, where it was first detected in Berks County, Pennsylvania, in 2014. The apple, grape, and peach industries in the states currently at risk for infestation bring in a combined $900 million annually, according to the USDA farm cash receipts data. This figure doesn’t include damage to the many host plants that spotted lanternfly may target, of which 70 have so far been identified. The pest also poses a threat to a variety of hardwood trees including maple, poplar, walnut, and willow.
After piercing into the bark of a tree or vine, spotted lanternflies suck out sap. While feeding, they excrete honeydew, a sticky, sugar-rich liquid that drives the growth of black sooty mold that further damages plants. Anecdotal accounts from growers indicate that yield loss on plants swarmed by lanternflies is severe. Some estimates put the potential damage in the billions of dollars.
Reports of spotted lanternfly distribution extend as far north as New York and Massachusetts, as far west as western Pennsylvania and West Virginia, and as far south as Virgina. Businesses operating within counties listed as quarantine zones in Pennsylvania are required to obtain a spotted lanternfly permit to move vehicles, equipment, and goods into and out of the quarantine zone. Getting a permit requires employees of businesses to take a training course on how to ensure that they are not carrying spotted lanternfly to and from various worksites.
At the moment, pesticides and citizen reporting from quarantine zones and surrounding areas to state agricultural extension officials are helping to keep the spread in check, but there is no certain method of eradication. However, a newly sequenced genome of the spotted lanternfly may give clues as to effective control methods. The USDA has also begun pilot testing introducing a parasitic wasp from Asia that preys on spotted lanternflies in their native range.
State agricultural officials farther afield are worried. An analysis of environmental conditions in which the spotted lanternfly could thrive suggest the pest could reach as far north as northern Michigan, as far south as Florida and Texas, and as far west as Colorado. There are also concerns that spotted lanternfly could reach the West Coast, where it could pose a substantial risk to the big apple-producing regions of Washington. California’s Central Valley also would be a suitable habitat for spotted lanternfly, potentially posing a risk to that state’s apple, wine, tree fruit, and tree nut industries, according to the USDA.
Apples are a major industry in states where spotted lanternfly has become infested, or threatens to do so. This tree map shows farm cash receipts from the apple industry in several of those states.