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Scientists issue warning about dangers beetle poses to Illinios ash trees

Jim Barlow, Life Sciences Editor


CHAMPAIGN, Ill. — Campers across Illinois are being asked to be firewood wary. There could be an unwanted pest hidden inside that could be devastating to the state’s 118 million ash trees if it emerges later this summer from unburned wood.

The pest is the emerald ash borer (Agrilus planipennis), an exotic, half-inch-long beetle. It has not yet been found in Illinois, but it has destroyed as many as 10 million ash trees in Michigan since 2002. It has spread to northeastern Indiana and northwestern Ohio.

Visitors to state parks will find 3-by-2 foot “Firewood Warning” posters displayed in campgrounds and picnic areas, said James Appleby, an entomologist at the University of Illinois at Urbana-Champaign and emeritus scientist at the Illinois Natural History Survey. Homeowners who obtain their firewood privately or haul it in by themselves also should be cautious, he said.

“This is an extremely serious pest,” Appleby said. “If this beetle is allowed to get into the state, it will be devastating. Travelers to Michigan could inadvertently transport the beetles back here in firewood they obtained in Michigan or as passengers that flew in through an open window.”

The borer spends the winter in larval form under the tree bark. Adult beetles emerge from the wood from mid-May until late July. Firewood from ash trees cut in Michigan could harbor borer larvae or adults that are about to emerge.

Appleby, who is part of a team that has surveyed the damage in Michigan, said that some property owners in the affected areas are not aware of what killed their trees and may be giving away wood to visitors to their homes.
It is the casual movement of firewood from Michigan that has officials in neighboring states worried, Appleby said.

While most firewood dealers honor the quarantines in the affected areas, some wood may be leaving illegally. The larvae, Appleby said, can still be present in trees cut down several months earlier.

The emerald ash borer, a native of eastern Asia, appears to be dark green in color when under bright light. Signs of infestation are D-shaped holes about one-eighth inch across on large branches and trunks. Under the bark, the larvae leave S-shaped tunnels, known as serpentine larval galleries.

Infested trees, depending on their size, may not show physical damage for two years. Thus avoiding wood from Michigan now is imperative, because once the beetles establish themselves the state’s ash trees will be in trouble, Appleby said.

Appleby and colleagues Phil Nixon, an entomologist in the department of natural resources and environmental sciences, and Charles Helm of the Natural History Survey have monitored the damage in Michigan. They’ve also been working with state and federal officials to try to prevent or deal with any infestation in Illinois.

The emerald ash borer often is confused with the brilliant green tiger beetle, a native insect often seen on the ground in open areas.

More information about the emerald ash borer is available through a USDA Forest Service Web site devoted to the borer and a site run by officials in Indiana, Michigan and Ohio
Copyright photos of the beetle and related damage, taken by Appleby, can be seen online.

Anyone who has Michigan firewood or suspects the presence of the emerald ash borer should call 312-742-3385 (the Plant Protection and Quarantine division of the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service), the Illinois Department of Agriculture at 800-641-3934, a local forester of the Illinois Department of Natural Resources, or a local U. of I. Extension office.