What to know about the spotted lanternfly, the insect experts say to squish

Scientists have a message about the spotted lanternfly: If you see one, squish it.

While that may sound harsh for bug lovers out there, experts say spotted lanternflies can be devastating to agriculture.

"It's a good idea if you can kill them, to do that," Brian Eshenaur, a senior extension associate for ornamental crops at Cornell University's pest management division, told ABC News.

The New York City Parks Department offers similar guidance on its website.

"Harming our city's wildlife is broadly prohibited, but in an effort to slow the spread of this troublesome species, the current guidance remains: if you see a spotted lanternfly, please squish and dispose of this invasive pest," the department says.

New York state's Department of Agriculture and Markets, Department of Environmental Conservation and the Office of Parks, Recreation, and Historic Preservation launched a program this year to train volunteers on how to identify and track the invasive species in the state.

The invasive species originated in Asia but was first found in the U.S. in Pennsylvania in 2014 and soon after in other states in the Northeast, including Connecticut, Delaware, Maryland, New Jersey, New York and Virginia.

The insect, known scientifically as the Lycorma delicatula, feeds on at least 70 different species of trees, as well as vines and shrubs, including fruit trees, grapevines and several hardwoods, according to a report from the University of Michigan.

The lanternfly isn't dangerous to people and pets, experts say. The insect is viewed as more of a nuisance since they don't bite or sting.

So if you plan on being vigilant for spotted lanternflies this summer, here are some key things to know.

Keep an eye out in backyards and parks

The bugs gather in large numbers and can be found in backyard trees and in parks, where they feed on trees and ooze a sugary substance called honeydew, which then can cause a sooty mold that can land on lawn furniture or your car, Eshenaur said.

The female lantern fly can lay between 30 and 50 eggs each, usually between September and October. The eggs hatch in the spring, where baby lanternflies called nymphs emerge, before becoming fully grown around July, according to the Washington State Noxious Weed Control Board.

They favor warmer temperatures

Climate change could exacerbate the problem, experts say.

"The spotted lanternfly needs a long growing season to complete their lifecycle," Eshenaur said. "With earlier spring and later fall frost that could favor the development of the lanternfly and increase the range in which they can survive at."

Insect development depends on the temperature, Kelly Oten, assistant professor in the Department of Forestry and Environmental Resources at North Carolina State University, told ABC News.

"As the temperature is warm, their development increases, which means they're going to actively feed for longer periods of time, potentially causing more damage," Oten said.

They're a threat to agriculture

Wine lovers, here's some bad news.

The spotted lanternfly can be devastating to the multi-billion-dollar wine industry since they feed on grapes, reduce their crops and diminish the quality of grapes, according to Oten.

Overall, they're a huge threat to agriculture. If the species were to spread through Pennsylvania, the expected losses to the state's economy would be nearly $554 million a year and potentially lead to the loss of 4,987 jobs, according to a 2019 impact study from Penn State University.

For forestry, the estimated economic loss could be up to $152.6 million annually throughout Pennsylvania, the study found.

What to do if you see one

Killing the pest if you encounter it isn't the only way to address the problem.

People should check outdoor items for spotted lanternfly eggs, which can look like a mass covered with gray wax. Scrape them off, put the mass in a plastic zippered bag with hand sanitizer and throw it out, the U.S. Department of Agriculture says.

While spotted lanternflies can't kill trees, they can cause damage to them. People can also use insecticides approved by the Environmental Protection Agency, which can kill lanternflies and not harm trees.