What you need to know about spotted lanternflies

Spotted lanternflies have grown in numbers to the point that all but one county in New Jersey have confirmed populations, with some counties under quarantine.

Now that these insects have made themselves known throughout campus, George Hamilton, chair of the Department of Entomology, explained the impacts of spotted lanternflies and what should be done to counter their spread.

The spotted lanternfly is an invasive insect from China, India and Vietnam that feeds on sap from various plants such as grapevines and maples. It was first found in the U.S. in 2014 in Berks County in Pennsylvania and reportedly spread to New Jersey in 2018, likely via hitchhikers or moving vehicles between the two states, Hamilton said.

It was then found on campus in 2019 in the wooded area between Loree and Foran Halls on Douglass campus, he said. Since then, the spotted lanternfly population has grown exponentially, spreading across all five campuses.

“It is common for exotic organisms when they are introduced to a new area to rapidly expand in numbers and geographic area,” Hamilton said. “Usually, this is because the organisms ... that keep them in check in the native range are not present in their newly introduced area.”

Lanternflies, like other invasive species, have caused significant damage to their new environment. Scores of flora have been affected, with agriculture officials in Michigan warning that these insects could kill more than 70 types of plants.

“Left unchecked, it has the potential to harm plants due to the removal of large (amounts) of fluids while feeding. Their feeding has already caused damage to vineyards in (Pennsylvania),” Hamilton said.

During this feeding, spotted lanternflies release a sugary substance called honeydew, which is what kills leaves, trees and other flora, potentially getting on cars and other outdoor objects as well, he said.

“A black mold called sooty mold then develops that is unsightly, may stain … and interfere with plant photosynthesis, ultimately inhibiting plant growth,” Hamilton said.

The spotted lanternflies will disappear from sight in late October and return next year, possibly with larger numbers, he said. Though, they may appear as adults until December with their distinctive spotted red and gray wings.

Several methods have been found to help curb their growth. Sticky tape and herbicides have demonstrated effectiveness. Praying mantises and yellow jackets can also kill lanternflies, though they may consume more than intended.

Another potential method is the "trap tree," used in South Korea to kill invasive insects, according to the article. The method involves poisoning a few trees with insecticide in order to kill the lanternflies as they feed.

Additional methods for killing spotted lanternflies and preventing their spread can be found on the New Jersey Department of Agriculture website.

“We recommend that people try to kill as many as they can when they see them,” Hamilton said. “This activity won't solve the issue of their (presence) on campus, but it will help.”