Slowly but surely, the Japanese beetle is advancing across Illinois.

Rhonda Ferree, extension educator in horticulture, said the Japanese beetle has been causing damage in places such as Peoria, Jacksonville and Quincy. The beetle has been around the United States since the early 1900s and has been in the Champaign area for the better part of a decade. The creatures, though, have recently been inching their way into West-Central Illinois, she said.

“This is the first year we’ve seen them in this area,” Ferree said. “But they’re here to stay.”

Travis Cleveland, former member of the University’s Horticulture Club and graduate student, said the beetle is a non-native species that was introduced to New Jersey. Lacking many natural enemies, the insect is able to spread.

“They have a great abundance,” he said. “And slowly they are kind of advancing across the country.”

This particular half inch-sized beetle is small, shiny and metallic green in color with bronze wing covers.

The adult beetle will feed on leaves of various plant life, such as linden trees and roses. While the adult beetle will feed on tissues of leaves leaving only the veins, the larvae will feed on roots of grass and turf, Ferree said.

Mike Kwiatek, a grower in Horticulture Club and senior in ACES, said Japanese beetles leave a lot of holes in the plants. He said most people who have a lot of damage done to their plants also have a lot of beetles.

“They feed on basically most green things they find,” he said. “They’re an invasive species. Their damage is in their numbers.”

Ferree said the beetle feeds top-down on trees because it likes to soak up the sun. Therefore, affected trees can be identified by a lack of leaf tissue on the top half of the tree — the bottom half may look completely green.

Ferree said the adult beetle will come out in June and feed for six weeks, while the larvae will come out in August. She added that the larvae will turn into a pupae in late spring and emerge as an adult beetle in June.

Gardeners may pick out the Japanese beetles if they are feeding on small plants or they can drown the insects in soapy water, Ferree said.

With larger trees, pesticide sprays will work better. “On a large tree, it’s hard to do that (pick the beetles out) with large numbers,” she said.

Cleveland said using insecticides is a last resort because it could be extremely toxic to beneficial insects.

Kwiatek said the damage done by the Japanese beetle cannot be reversed.

“You can remove the dead leaves, but the actual damage is done,” he said.