Emerald ash borer poses serious danger to Pa. trees

By Dane Mitchell

November 28, 2008 03:35 pm

American ash trees are in danger. Twenty million were lost in Michigan alone in the first years of the onslaught of an invasive pest, the emerald ash borer.
This brilliant green insect, only one-half inch in length, has been sweeping unchecked through Midwest forests, parks, and suburbs.
Although it can fly only one-half mile, this beetle has covered Michigan, Illinois, Indiana, and is moving rapidly through Ohio. In 2007 it was found in Pennsylvania, and last June in Mercer County. 
How does it travel so extensively? Simple: We help.
The emerald ash borer probably arrived from Asia in wooden packing material, and is moved around by people transporting firewood, logs, or nursery stock.
How can we stop its rapid spread? Do not move firewood.
The Pennsylvania Department of Agriculture has imposed a firewood quarantine on five countries: Mercer, Butler, Beaver, Lawrence, and Allegheny. This means there is a fine, and possibly a jail sentence, for transporting any hardwood firewood out of these counties. It is also illegal to transport ash logs out of these areas. 
What will the ban on moving firewood accomplish? It can buy time. Time is needed for scientists to establish a method of attacking the emerald ash borer and save the ash trees. 
The white ash, a common tree in Pennsylvania parks and woodlots, is useful for baseball bats, tool handles, sports equipment, and even furniture. Its loss would weaken diversity, needed for forest health.
How can we identify the presence of the emerald ash borer?  The shiny green coat of the adult insect is visible in summer. Its shape is rather like a fireplug.
Nearly white, the larvae are about one inch long, and may be found year-round. Feeding under the bark, they mark visible S-shaped tunnels, destroying the trees ability to transport nutrients in the cambium layer, where growth occurs. The adult beetle leaves a distinct one-eighth inch D-shaped hole as it exits the tree.
Dieback in upper branches is seen in a year, and in three years the tree can be killed. Although some success has been achieved with chemical treatment in parks and residential areas, no treatment is yet practical for Pennsylvania’s woods.
If you suspect you have found the emerald ash borer, call the Pennsylvania Department of Agricultural toll-free hotline at 1-866-253-7189, or USDA Forest Service at 1-866-322-4512. 
Save the ash tree. Observe the law. Don’t move firewood out of Mercer County.

Dane Mitchell is information assistant with Mercer County Cooperative Extension.

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