I just read about the emerald ash borer (EAB) appearing in Oregon. We have two large very nice ash trees that we don't want to cut down, no signs of infestation at this time. Would you recommend we go ahead and treat these with the pesticide injection that treats for the borer, just in case?
Right now, we suggest only treating the trees when the insect has been reported within 10 miles or so of your location. Currently, EAB only appears to be in and nearby Forest Grove. See What to do about emerald ash borer: Recommendations for tree protection in EAB-infested areas for a list of treatments for EAB and guidance on when to remove ash trees.
The insect spreads when adults are flying during the period from May to September, so after this summer we will have a much clearer understanding of how the situation has developed. The Oregon Department of Agriculture and the Oregon Department of Forestry are monitoring this invasion closely.
Therefore, depending on where you live, you might wait until later this summer/early fall when we have more information.
Slowing the spread of emerald ash borer
Here are some tips for reducing the spread of emerald ash borer:
- Avoid planting new ash trees. Read our new publication Alternatives to Ash in Western Oregon for suggestions.
- Do not move firewood across the state. This is a common way that wood-boring insects are transported to new counties. Instead, purchase firewood nearby the recreational area where you are planning to build a fire. For more information, visit DontMoveFirewood.org.
- Learn how to properly identify emerald ash borer and report sightings. If you feel confident you have EAB, please report sightings at the Oregon Invasive Species Council Hotline. Please consult the EAB look-alikes guide from Oregon Department of Agriculture before reporting.