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Emerald Ash Borer: past, present and future

July 2, 2018 7:17 AM

Have you heard about EAB? The Emerald Ash Borer or EAB is an exotic beetle first discovered in the United States in the summer of 2002 in southeastern Michigan near Detroit. As of May 2018, EAB has been confirmed in 33 states and the Canadian provinces of Ontario, Quebec, and Manitoba. The adult beetles cause little damage.  The larvae (immature stage) is the real threat to the tree. They feed in the inner bark disrupting the tree's ability to transport nutrients and water. 

Where is EAB in Madison? The real question - where does it not exist in the city? Emerald Ash Borer was first confirmed in November 2013 in Madison.  This also marked the first EAB find within Dane County.  Since then, EAB has been discovered in many other cities, villages, and towns across Dane County.  As of March 2018, 48 of Wisconsin's 72 counties are confirmed to have the EAB and the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) placed the entire state under quarantine

With the entire state under quarantine, wood can move freely between counties within Wisconsin. Businesses that move regulated items out of state will need to work with USDA Animal and Plant Health Inspection Service to confirm interstate requirements. These are items such as ash wood with bark, larger ash chips, and any kind of hardwood firewood. Firewood restrictions will remain on state and federal lands.  DATCP recommends campers that they buy firewood that bears the DATCP-certified mark, which means it is seasoned or heat-treated to kill pests and diseases (EAB, oak wilt, Thousand Cankers Disease, etc.).

The City of Madison Parks Forestry Section has been treating ash street trees that have met the treatment criteria and preemptively removing ash street trees since 2014.  The latest map highlights areas of planned removals in 2018 and 2019. As forestry continues to carry out the EAB Mitigation plan, routine pruning requests by property owners will be completed when forestry resources are available.

Without a doubt, EAB will affect every ash tree in the community, public or private.  It is difficult to detect newly infested trees because they show few if any, external symptoms. The first sign of an infected ash tree may be noticed when woodpeckers are feeding on the larvae and creating jagged holes in a tree's trunk during the winter.  As the EAB population grows in the tree, leaves wilt, branches die, and the tree canopy becomes increasingly thin. Sprouts of leaves may rise on the trunk or branches of the tree. If you see D-shaped exit holes at eye level of a tree trunk, the infestation is heavy and has been there for several years and treatment of the tree may not be effective. For more information on EAB, you can visit EAB the Emerald Ash Borer Information Network.

We always appreciate the support Madison residents provide to the urban forest. That is what makes Madison so great!


Marla Eddy
City Forester



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