Scientists examine potential economic impact of spotted lanternfly in Pa.

Amy Duke
January 15, 2020

UNIVERSITY PARK, Pa. — If not contained, the spotted lanternfly potentially could drain Pennsylvania’s economy of at least $324 million annually and cause the loss of about 2,800 jobs, according to a study carried out by economists in Penn State’s College of Agricultural Sciences.

According to the researchers, under a worst-case scenario, in which damage reaches the maximum projected by crop-production and forestry experts, these losses could increase to $554 million annually and almost 5,000 jobs.

The report, the first to estimate the potential financial ramifications of the spotted lanternfly — an insect that has an insatiable appetite for the sap of fruit, ornamental and woody plants — also places current economic damages due to the pest at $50.1 million per year with a loss of 484 jobs in the southeastern part of the state.

“Even if the worst-case scenario doesn’t come to pass, the spotted lanternfly already has inflicted millions of dollars in damage to our state’s agriculture and forestry industries,” said Jayson Harper, professor of agricultural economics and director of Penn State’s Fruit Research and Extension Center

“Our findings demonstrate that the vigorous response by the Pennsylvania Department of Agriculture, U.S. Department of Agriculture, Penn State and industry stakeholders to limit the spread of spotted lanternfly is clearly warranted — our economy depends on it.”

Native to Asia, the spotted lanternfly first was discovered in the U.S. in Berks County in 2014 and has spread since to Bucks, Carbon, Chester, Dauphin, Delaware, Lancaster, Lebanon, Lehigh, Monroe, Montgomery, Northampton, Philadelphia and Schuylkill counties, all of which are under a state-imposed quarantine.

A team approach: Direct, indirect and induced impact

Harper and Timothy Kelsey, professor of agricultural economics and co-director of the Center for Economic and Community Development at Penn State, Lynn Kime, senior extension associate in agricultural economics, and William Stone, an undergraduate student majoring in community, environment and development, conducted the study. They used data from government reports, crop-production experts, industry surveys, and interviews with stakeholders and Penn State researchers and extension educators to come to their conclusions.

The team evaluated direct impact, defined as the value of lost crops and revenue to farmers and forest landowners; indirect impact, such as decreased purchase of goods and services from businesses that support those growers; and induced impact, which focuses on reduced household spending due to lost work hours and household income.

Three scenarios: Estimated overall impacts to PA economy

Their predications are modeled on three scenarios: if spotted lanternfly is contained successfully to the current 14-county quarantine zone; if it spreads to the neighboring counties of Adams, Columbia, Cumberland, Franklin, Lackawanna, Luzerne, Montour, Northumberland, Perry, Pike, Wayne and York; and if it reaches all 67 counties in Pennsylvania.

Using an economic-assessment software program called IMPLAN, the economists examined the overall impact of spotted lanternfly on the economy, combining direct, indirect and induced effects.

In the quarantine zone, that damage currently is estimated to be $50.1 million total per year with a loss of 484 jobs. If the worst-case scenario occurred, these losses would be expected to increase to $92.8 million total per year with a loss of 927 jobs.

If the insect spreads into the adjacent counties, expected losses would increase to $89.2 million total per year with a loss of 843 jobs. If the worst-case scenario occurred, these losses would increase to $168.8 million total per year with a loss of 1,665 jobs.

If it spreads throughout Pennsylvania, the expected losses would amount to $324.9 million annually with a loss of 2,810 jobs. Under the worst-case scenario, losses could increase to $554.0 million, with a loss of 4,987 jobs.

Current direct impacts to PA agriculture

When calculating direct impacts of spotted lanternfly on Pennsylvania’s agriculture, the team used data from USDA’s 2017 Census of Agriculture and a survey of crop-production experts. The scientists determined that the estimated overall annual direct economic impact of spotted lanternfly damage on Pennsylvania agriculture currently is $13.1 million in the quarantine zone, $7.7 million in the adjacent counties, and $42.6 million statewide.

Agricultural sectors that are taking the brunt of those losses include nursery operators, to the tune of $8 million in the quarantine zone and $22.9 million statewide, fruit growers — especially grape growers — and Christmas tree growers.

Spotted lanternfly on grapevine

 Spotted lanternflies, seen here feeding on a grapevine, threaten Pennsylvania agricultural crops and forest products.

IMAGE: Erica Smyers

If the worst-case scenario occurs, the overall annual agricultural losses due to spotted lanternfly would be an estimated $29.6 million in the quarantine zone, $20.4 million in the adjacent counties, and $99.1 million statewide.

Impacts on the state's forest products industry

To calculate the direct impacts on the Pennsylvania forest products industry, the researchers used data from the U.S. Department of Agriculture’s Forest Inventory and Analysis database, quarterly price data from the Pennsylvania Timber Market Report, and a survey of forest-products experts.

The overall annual impact of the spotted lanternfly feeding on forest trees is estimated to be $16.7 million in the quarantine zone, $15.6 million in the adjacent counties and $152.6 million statewide.

While researchers are working to understand the direct long- and short-term impacts that spotted lanternfly has on its various host plants, the pest’s feeding may cause considerable economic damage to forests over time, especially to soft maple, various oak species and black walnut.

If the worst-case scenario occurs, then the overall annual impact on forest trees would be an estimated $25.8 million in the quarantine zone, $25.2 million in the adjacent counties and $236.3 million statewide.

The best approach: Implementing best management practices

The study also looked at the cost to implement best management practices, which include employee education, pest monitoring and inspection, phytosanitation, and removal of Ailanthus altissima, commonly called tree of heaven, a preferred host of the pest. The team came up with estimates ranging from $27.9 million in the quarantine zone to $219.6 million statewide, depending on the industry sector and geographic location.

Kelsey emphasized that while figures in the study are preliminary and are subject to change as crop-production experts improve their understanding of the impacts of the spotted lanternfly, it’s important to recognize that even if the actual production losses are lower than initial estimates, the scale of these numbers is large enough that the impacts still will be significant.

“The potential spread of this pest argues for the continuance of existing programs, the strengthening of research and management efforts, and additional funding,” he said.

The study was funded by the Center for Rural Pennsylvania, a legislative agency of the Pennsylvania General Assembly. The full report can be found on the center’s website at

More information about the spotted lanternfly can be found on the Penn State Extension website at

(Media Contacts)

Last Updated February 11, 2020