Ken Alleman's livelihood may suffer a serious blow due to the spread of a small metallic-green beetle -- a beetle that has been found in La Salle County.

Alleman, owner of Tonica Nurseries, said he has thousands of ash trees in his stock.

"They're our native tree," he said. "They're strong. You can make axe handles from them. They have a nice color. They are fast-growing. They are the perfect tree."

But the future of these trees in the county is in question, as the Illinois Department of Agriculture announced Wednesday it found the tree-killing emerald ash borer just north of Peru at the intersection of Interstate 80 and Route 251.

"Our staff now is surveying ash trees in the surrounding area to define the size of the infestation," Agriculture Director Chuck Hartke said in a statement.

The larvae of the emerald ash borer, native to Asia, kill ash trees by burrowing into their bark. Though the tree ties, the wood still may be used for several purposes.

The invasive insect has killed an estimated 20 million ash trees since it was first confirmed in the Midwest in the summer of 2002.

The beetles first were spotted in Illinois in June 2006 in rural Kane County. They since have been found in the northern Cook County communities of Wilmette, Evanston, Winnetka and Skokie.

Hartke said the department has imposed a quarantine in parts of five counties to stop the movement of ash wood and live ash trees or saplings out of infested areas. It also is removing infested trees at no expense to homeowners and making a comprehensive survey of ash trees in northeastern Illinois, he said.

Alleman believes the infestations will move along the interstate highways, since the insects often are in pallets and firewood shipped via trucks. Tonica Nurseries is across the road from a truck stop along Interstate 39.

While it hasn't yet arrived at his business, "I'm sure it will. It follows the interstates. It's here to stay," he said. "It's a nasty insect."