URBANA, Ill. — A moderately-populated area of spotted lanternfly (SLF), an invasive insect that preys on a variety of orchard items including pumpkins and grapes, was identified by the Illinois Department of Agriculture (IDOA) on September 16. 

“Spotted lanternfly has been inching closer to the Midwest and Illinois for close to a decade,” said Jerry Costello II, Illinois Department of Agriculture (IDOA) director, in a Sept. 26 news release. “We have had a multi-agency team working to prepare for this scenario — including efforts on readiness, informing and educating the industry and the public, as well as monitoring early detection.”

An invasive plant-hopper from Asia, SLF was first found in the U.S. in Pennsylvania in 2014. More recently, SLF populations were confirmed in Indiana, Michigan and Ohio. According to the IDOA, SLF feeds on a wide variety of plants but displays a strong affinity for the invasive tree of heaven and maple trees, in addition to orchard fruits and vegetables. 

The University of Illinois Extension hosted a webinar to inform Illinois agricultural producers, arborists and landowners about what to look for to determine the presence of SLF, along with how to respond. “SLF feeds on sap, so one of the things you end up having are very sticky plants. Then come ants, stinging wasps and (other sap-loving insects),” said Kacie Athey, a specialty crop entomologist with the U of I College of Agricultural, Consumer and Environmental Sciences (ACES). 

“In addition to any actual damage this does to the plant, this can be an issue for agritourism because not only do you have these sugar-loving insects on your plants, but then you’re getting (wasps) as well. It also decreases the photosynthetic processes within the plant,” she added.

Producers can look for SLF eggs, nymphs and adults on their plants, with adults active from late July into November. This period is also when egg-laying takes place, before eggs overwinter in place before hatching around mid-April. 

“In terms of pest status, it’s the adults that are actually doing the most harm to the plants,” Athey said. “This is kind of different from (the behavior) of some of our other insect pests where nymphs and larvae do the most actual damage to the plants.”

Interestingly, the SLF’s main “tree of choice” for feeding— the tree of heaven (Ailanthus altissima) — is itself an invasive species. “The tree of heaven is an invasive plant that does a lot of damage here, and is really widespread. It’s known as stinking sumac, Chinese sumac, varnish tree or stink tree because it has a strong, somewhat offensive odor that comes from its flowers. Its presence here really has advanced the spread of SLF.”

Illinois is highly suited for SLF, the entomologist explained, because of the widespread distribution of the tree of heaven. While it would be better if the voracious pest would feed exclusively on the tree species, it instead serves as a beacon to the SLF, which does not discriminate between nuisance plants and cash crops when it comes to feeding. 

While SLF in all cycles of life have been discovered only on the tree of heaven and in grape orchards, they have been known to feed on “common” trees and standard garden vegetables, according to researchers. 

The IDOA is asking producers and the public to report suspected sightings or infestations of SLF to lanternfly@illinois.edu. In addition to checking plants and trees, vehicles, boats, campers and other outdoor articles can be monitored for the presence of SLF. Insects, eggs and nymphs should be photographed and reported before being destroyed. 

According to U of I entomologist and ag pest survey coordinator Kelly Estes, the response from the public in reporting suspected SLF sightings has been impressive. “People have been sending photos and reports, especially in northeastern Illinois where we did confirm a small population in Cook County. We’re following up on these reports,” she said, adding that reports of deceased SLF carcasses are coming in as the weather begins to cool. 

Researchers will focus on identifying locations of egg masses and collecting specimens over the coming winter. This will help them to determine where SLF is likely to resurface within the state come next spring, Estes said.