Tree Tips, Notes and News

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Tree Tips, Notes and News


Yes, the Emerald Ash Borer is here.

The emerald ash borer has been found in Pennsylvania. As well as Michigan, Illinois, Indiana, Kentucky, Maryland, Minnesota, Missouri, New York, Ohio, Virginia, West Virginia, Wisconsin, Ontario and Quebec. Originating from northern China, Japan, Korea and eastern Russia, prior to 2002 it was not found in the United States and likely came here in shipping cargo around that time.

All species of the North American Ash are being infected. Although stressed or weak trees are preferred, healthy Ash trees are susceptible as well.

The ash borer has a 1 to 2 year life cycle. Adults begin emerging in mid to late May and peak by late June. Females usually begin laying their eggs about 2 weeks after emerging and the eggs hatch in about 2 weeks. The larvae bore through the bark and into the cambium (the area between the bark and the wood). Nutrient levels are high there and the larvae feed for several weeks. They over-winter in a small chamber in the outer bark or within the outer inch of wood. Pupation begins in spring and the new generation adults emerge mid to late May. The adults can fly 1/2 mile or more from the tree where they emerge. The adult beetles leave a "D" shaped exit hole in the bark, roughly 1/8 inch in diameter, when they emerge in June.

Although this might be difficult to see because of their size. The adult beetle is a dark metallic green color - 1/2 inch long and 1/8 inch wide.

What can you do? Careful monitoring of your Ash trees throughout the season will help. Buy local firewood only. Chester County, so far, has not been quarantined. Call right away if you think you see any of the signs or symptoms.

Early detection is essential.

What to look for? Die-back on the upper third of the tree, (the borer destroys the water and nutrient conducting tissues under the bark), D-shaped exit holes in the bark where adults emerge (photo on previous page), vertical splits in the bark, and serpentine-shaped tunnels beneath the bark in the cambium, (see photo below) where larvae effectively stop food and water movement in the tree, thus starving it to death. It takes 1-3 years for the infested tree to die.

For additional research the following links provide a wealth of information:

Pa Dept of Agriculture fact sheet

Penn State Tree Identification fact sheet

Penn State Emerald Ash borer information

Penn State Emerald Ash borer fact sheet

Pa DCNR fact sheet

Pa Dept of Agriculture Quarantine Map

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