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Emerald ash borer moves north, infested tree found in Superior

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nature Cloquet,Minnesota 55720
Pine Journal
Emerald ash borer moves north, infested tree found in Superior
Cloquet Minnesota 122 Avenue C 55720

SUPERIOR, Wis. -- A Chinese insect that has killed millions of trees in the eastern United States and Canada has been confirmed in Superior.


City of Superior crews found what they thought was a suspect ash tree on Aug. 7, and after investigating further, found what appeared to be ash borer larvae in the tree. They sent samples to the U.S. Department of Agriculture in Michigan, which confirmed emerald ash borer this week.

Superior city officials made the announcement today.

"This infestation is really going to change the landscape," Superior Mayor Bruce Hagen said in the announcement.

Until now, the closest the insect had been found to the Duluth-Superior area was the Twin Cities and southwestern Wisconsin near LaCrosse. Now the half-inch, metallic green bug appears to have jumped more than 100 miles quickly, leaving thousands of urban and suburban ash trees in peril and threatening huge swaths of forest comprised of black ash.

Experts said the insect can't move far on its own each year but probably has expanded its range so fast thanks to people unknowingly carrying the bug in firewood or live trees.

The Wisconsin Department of Agriculture, Trade and Consumer Protection has immediately placed all of Douglas County under quarantine to prevent infected trees and wood from moving into other areas.

The insect was first confirmed in Wisconsin in 2008 and now 20 counties are under quarantine.

Superior City officials note they have surveyed some 3,000 ash trees within the city. Those that have been hit by the insects will start dying within one to three years, officials noted.

The emerald ash borer -- a Chinese import that has killed millions of trees in Michigan, Indiana, Ohio and Illinois -- has no natural enemies here. And it seems North American ash trees have no natural resistance.

Adult flying beetles fly to ash trees and mate. They lay eggs on the tree and the larvae burrow into the tree, where they eat into the parts of the tree that carry water and nutrients into the canopy, eventually killing the tree. The larvae then burrow out and emerge as a flying beetle to spread the cycle to other trees.

Emerald ash borers have killed all sizes and all 17 varieties of ash found in the United States.

For more information on emerald ash borer, go to www.emeraldash

Ash trees with a dying crown or with major woodpecker damage are suspect. The bugs leave a distinctive, small D-shaped exit hole when they leave the tree. If you suspect emerald ash borer, make sure the tree is an ash tree and then use information on the Web to eliminate other tree problems. If you still suspect ash borers, contact the Minnesota Department of Agriculture at or call (888) 545-6684. In Wisconsin call (800) 462-2803.