We live in Woodbury mn. We have an ash and wonder if we should have it...

Asked March 21, 2015, 11:49 AM EDT

We live in Woodbury mn. We have an ash and wonder if we should have it treated to stop the ash bore. Is it necessary to do it now because I do not think it has reached this area yet? thank you

Washington County Minnesota

1 Response

Thank you for the question. I checked the Minnesota Department of Agriculture and University of Minnesota Extension websites and found that emerald ash borer hasn't been found in Washington County yet but it has been found quite close-within 5 miles. An ash within 15 miles of a current infestation is more likely to be attacked. See the map here http://gis.mda.state.mn.us/eab/
Before you arrange for a preventive treatment, there are a few questions you should ask:
  1. Is the tree a valuable part of your landscape?
  2. Is the tree planted in a location that allows for good future growth, without impacting structures (house, garage, etc.)?
  3. Is the tree healthy? Elongating branches, bark tightly held to the branches and trunk, and a full, dark green canopy of leaves.
  4. Is the tree free of apparent structural weaknesses?
    1. Is there only a central leader on the tree? If there are 2 or more leaders (called co-dominant stems) with a v-shaped crotch this will lead to failure of one or both stems. A 'U-shaped' crotch is good, strong and not problematic.
    2. Does the trunk have a normal basal flare (like a bell) at its base or does it go straight into the ground? If a tree trunk goes straight into the ground, this will cause the tree to decline once it gets to be 25-40 years old.
    3. Is the bark intact around the base of the tree? String trimmers and lawn mower damage eventually will lead to tree decline.
    4. Do the roots have plenty of room to spread and develop? Some ash trees are planted in the narrow strip between the sidewalk and the street, which is normally not enough room to grow properly.
If you answer yes to the above questions, then preventive treatments could be considered.

Please read this University of Minnesota Extension publication all about Emerald ash borer in Minnesota written by Jeff Hahn, Extension Entomologist: http://www.extension.umn.edu/garden/insects/find/emerald-ash-borer/about/ If you scroll down the publication, you will see the paragraph titled "Should I treat my ash?"

Thank you for contacting Extension.