Turf Pest of the Month: How to help slow the spread of spotted lanternfly

Mostly found in the eastern part of the country, the spotted lanternfly has slowly been making its way into midwestern states. In September 2023, researchers confirmed its presence in Illinois, the furthest west anyone has seen the SLF.

Ken Johnson

Considered a newer invasive species in the U.S., the spotted lanternfly (SLF) can be a major nuisance for both golfers and golf course superintendents. While the SLF isn’t going to directly damage your turf, Ken Johnson, horticulture educator at the University of Illinois Urbana-Champaign, says the insect can still harm it indirectly.

“As they feed on the trees, (the SLF) releases a lot of honeydew,” he says. “Once there is a lot of honeydew buildup, you’ll see a sooty mold growth. This sticky substance can further damage plants and turf around it.”

The honeydew, Johnson adds, can attract other insects that can damage turf or be a general nuisance to golfers and maintenance crews — like wasps and other stinging insects.

Trick and treat

According to Johnson, because the species is so new to Illinois, researchers are still looking at different ways to combat it. Illinois, he says, has followed the lead of other states — like Pennsylvania, where the SLF first entered the country in 2014 — in its initial handling of the insect. Superintendents have utilized insecticides with the active ingredient dinotefuran, which absorbs into the tree to combat potential infestations.

As far as contact insecticides go, Johnson says products featuring the active ingredients beta-cyfluthrin, carbaryl, zeta-cypermethrin and malathion, have proven to be successful.

“Those are all considered excellent, but if you want reduced toxicity, there are natural pyrethrin to choose from. There are also textile soaps and horticulture oils. Honestly, any oil is good to use,” he adds.

In addition to insecticides, Johnson recommends simple traps — sticky bands and circle traps — to catch the SLF before it can damage a tree.

Johnson calls SLF “showy insects,” meaning they’re not easily mistaken for any other golf course pests. Adult lanternflies sport gray wings with black stripes and spots on the tips. When they’re disturbed, superintendents will be able to see patches of red on the insect’s back.

Known as “plant hoppers” the spotted lanternfly has slowly spread across the U.S. since first appearing in Pennsylvania in 2014. (Photo: University of Illinois)

Prevent defense

For a more preventive approach, Johnson says superintendents should closely monitor trees on the course. If they find that insects have a favorite tree to feed on, keep an eye on it.

SLF specifically, he says likes to feed on ailanthus altissima, more commonly known as the “tree of heaven,” which is also considered an invasive species because of its ease of establishment and rapid growth.

“If a course has (a tree of heaven), that is something to monitor,” Johnson says. “If they haven’t removed those trees, the spotted lanternflies can lay a lot of eggs on it. Those eggs can be overlooked. Once they first show up, you may only have a few here and there, but the population can build. They’ll probably be more noticeable as those populations increase.”

Superintendents can identify SLF eggs by looking for light-brown or gray masses that can be up to 1.5 inches long. SLF will usually lay eggs on trees near their feeding site. Other areas to check are the underside of horizontal surfaces. After spotting these eggs, Johnson says the best course of action is to either scrape them off into a container filled with either rubbing alcohol or hand sanitizer or smash them.

He advises that superintendents start doing this at some point early in the fall and continue through May. This is because once April hits, juvenile SLF will start to emerge. Once active, adult SLF will start to lay their eggs in September, continuing through either November or until the first freeze.

Pest hotline

To help monitor the spread of SLF across the state, the University of Illinois has set up an email where superintendents can report sightings.

The university requests that superintendents send photos of spotted lanternflies to lanternfly@illinois.edu along with detailed information such as the time and location of the sighting and the number of insects.