Spotting and stopping the spotted lanternfly: A guide for homeowners

The Philadelphia region has faced a persistent and troublesome invader: the spotted lanternfly. Since the pest’s first appearance in Philly six years ago, the number of lanternflies has declined, but efforts to control the insect never stop.

Jason Parker, a certified arborist with the Davey Tree Expert Co. in Horsham, has been at the front lines of these efforts helping homeowners recognize and manage lanternflies.

Spotted lanternflies are relatively easy to spot, said Parker. “You see the trees and shrubs on your property every single day. You’re going to know when something’s not right because if it looks different than last week, last month, or last season, don’t let these little indicators make you think you’re being paranoid,” he said. “Call a specialist because oftentimes you’re catching it so early that we’re going to be able to help with a cure or recovery at that point.”

From when nymphs hatch in the spring until winter’s first frost, spotted lanternflies take on many appearances throughout their life cycle, leaving clues to their whereabouts.

Egg masses can appear on any flat surface like trees, stones, and patio furniture, which is why lanternflies are easily spread through cargo and vehicles. Look for patches of a white, claylike substance on flat surfaces from September through June. As egg masses dry out, their surfaces will crack and turn brown.

Lanternfly nymphs, which appear in the spring and grow up to a half-inch, are tiny wingless insects with black-and-white polka dots that could be mistaken for ticks or spiders. They’ll grow through four stages, or “instars,” until they resemble adult lanternflies with a vibrant red, black, and white color.

Adult lanternflies are active from July through December, growing up to an inch long with gray and black polka-dotted forewings and red and black hind wings.

There are no studies on the impact of lanternfly damage on homeowners, but they can stunt the growth of or deteriorate plants and trees beyond recovery, which can be heartbreaking for some, said Parker.

“It’s really interesting how personal people get with their trees, whether it’s a memorial tree for a pet or the day their baby was born,” he said. “Those trees mean a lot to people and it’s tough to help someone decide to get rid of one of those. That’s why we try to focus on preventative measures.”

Lanternfly eradication is a near year-round pursuit, involving killing the insect when it appears and treating a property with insecticides for larger populations. “Every lanternfly that you kill will be one less that can lay eggs,” Parker said.

For small numbers, swat lanternflies and scrape their egg masses from flat surfaces; be sure to dispose of egg masses in a sealed bag with alcohol or hand sanitizer. Additionally, kill two birds with one stone by removing the invasive plant species tree of heaven from the property.

“Thankfully lanternflies are easy to kill. I’ve seen plenty of parents hand their kids a flyswatter or tennis racket and say, ‘Go to town,’” Parker said. “But for larger quantities, you’re going to need a systemic control.”

There are plenty of home remedy recipes found online, like spraying soapy water or vinegar to ward off lanternflies, but Penn State’s spotted lanternfly management guide advises against it, encouraging the use of systemic pesticides instead.

Systemic pesticides like dinotefuran and imidacloprid can kill insects outright or through ingestion when insects feed on a treated plant. If using chemical control, Pennsylvania State University researchers recommend using only registered pesticides, which can be found in local stores. But, in the majority of cases, it’s safer for the environment and plants to hire trained professionals.