The adult ash borers eat the leaves of the tree, but they aren't the real problem, and only cause minimal damage. The real buggers are the larvae, which feed off the inner bark and disrupt the tree's ability to transport water and nutrients. By the time you see the adults, the damage has already been done.
Because of the numbers of trees already killed and the great threat posed, the USDA has imposed quarantines and fines on moving wood from infested trees. MN and WI state parks have banned out-of-state firewood in an attempt to prevent the transport of the beetles into the states. The insects are not strong flyers and can only make it about a half mile on their own, but humans tend to give them a lift - 80% of the infestations in Michigan, for example, were traced back to firewood.
Entomologists say the arrival of the emerald ash borer in MN is inevitable, and all species of ash appear to be susceptible. The loss of the ash tree would have a significant impact on our urban landscape (my backyard would be a completely different and much less appealing place!), but it would have an even more detrimental effect on our forests. In the river gorge, green ash is a common tree species, and prickley ash and black ash are also present.
For more information:
- http://www.emeraldashborer.info/ - a multi-state effort (MI, IL, IN, MD, PA, OH, WI) to provide the latest information on the emerald ash borer
- http://www.mda.state.mn.us/plants/pestmanagement/eab.htm
- MN Dept pf Ag's Response Plan and Strategic Plan, survey maps and tree traps
- http://minnesota.publicradio.org/display/web/2007/05/03/buggytrees/
- http://www.extension.umn.edu/extensionnews/2005/emeraldashborer07.html
http://www.ppdl.org/dd/images/eab.jpg, H. Russel, Michigan State University
http://www.michigan.gov/dnr/0,1607,7-153-10370_12141-69866--,00.html
http://www.cas.vanderbilt.edu/bioimages/image/f/frpe--lf13383.htm, Steven J. Baskauf