Emerald Ash Borer

Emerald Ash Borer (EAB) has recently been in the local news again. The City of Quincy began having city ash trees treated earlier this month and a comment was made by the applicator that they believed that EAB was already in Quincy. Since that time, I have been in contact with the Illinois Department of Agriculture and at this time as of June 24, 2015 EAB has NOT been confirmed in Quincy. People will ask if it could be here and yes it could, but we just haven't found it as of yet. Of course one of the major questions is how can I protect my trees from Emerald Ash Borer.

It is recommended that treatment begin once EAB has been positively identified within 10-15 miles. Treatment earlier then this not necessary and even if EAB is discovered in an area closer than 10-15 miles, there is still time to begin treatment of trees. It should be noted that treatment is not a one-time event, but an every year or every other year practice for the life of the tree. Homeowner treatments fall into the every year category.

There are limited options for homeowners to treat their own trees and the ability to treat the tree depends on the size of the tree. Trees that are over 15" are best treated by a professional as homeowner products are not effective for larger trees. To figure out the size of your tree measure the diameter of the trunk 4.5' above the ground which is diameter at breast height or DBH. The easiest to use homeowner product contains the active ingredient Imidicloprid. The best time to treat ash trees is in the spring – apply products labeled for use on ash trees for control of EAB when leaves are about ¾ expanded or right after ash are done blooming for best uptake. If you have a tree larger than 15" DBH, contact a local certified professional to discuss options for treatment.

If you chose to treat your trees yourself there are a few tips to applying the product:

  • Make sure to pull back any mulch or other organic matter such as turf or fallen leaves as imidiclorpid will bind with those materials becoming unavailable for the tree to take up. Rake a 1 foot diameter ring to expose bare soil and apply to that area.
  • Soil should be moist but not water logged
  • Avoid application if heavy rains are expected within 24 hours to avoid the product from washing away
  • Do not apply within 25 feet of bodies of water such as lakes, ponds, streams, etc.

Also be aware of common signs and symptoms of EAB infestation:

  • Canopy Thinning
  • Bark Splits
  • Epicormic Shoots
  • Woodpecker Damage
  • 1/8 inch D-shaped exit holes in bark
  • Feeding notches on the edge of leaves
  • S-shaped larval feeding galleries underneath the bark

If you are not sure if you have an ash tree, you are concerned about EAB, have questions about it, please contact your local Extension office. If you are in the Adams, Brown, Hancock, Pike or Schuyler County area, you can contact me directly at 217-322-3381 or via email at khoule@illinois.edu .