Saturday, June 17, 2006

Emerald ash borer (EAB)

All Illinois tree admirers gave a collective shudder with the announcement of the discovery of the nefarious emerald ash borer within our state. The Illinois Department of Agriculture (IDOA) made the June 13th announcement indicating the beetle had been found in a yard of a Kane County home east of Lily Lake. This insect, originally from Asia, has become a significant ecological concern to our region. First detected in June 2002 in the Detroit area, arborists and scientists have since been tracking the appearances of this insect. As noted by the IDOA announcement “The emerald ash borer is a small, metallic-green beetle native to Asia. Its larvae burrow into the bark of ash trees, causing the trees to starve and eventually die. While the beetle does not pose any direct risk to public health, it does threaten the tree population. Since the emerald ash borer was first confirmed in the Midwest in the summer of 2002, more than 20 million ash trees are dead or dying.” Curiously, in the insects’ native range of Asia, it attacks and kills trees that have already been stressed and weakened while in North America, this insect attacks healthy trees. Considering that an estimated 20% of street trees in the Chicago area are ash, the significance of this insect announcement and outbreak is great!
Further reading --

If you are making some plant selection decisions, you may wish to review the article Alternative to Ash (Is emerald ash borer affecting your ash trees? A Purdue University horticulture professor emeritus offers a list of 13 trees that could be used as substitutes for Fraxinus in the landscape.) by Harrison Flint in the June 15, 2006 issue of American Nurseryman.

For a global view of species invasions, read Yvonne Baskin's
A plague of rats and rubbervines : the growing threat of species invasions, 2002. In this work, Baskin explores the environmental toll and consequences of our shrinking, mobile world.

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