Birch borders

Asked October 18, 2020, 8:17 PM EDT

We believed we have the Birch borer in 2 of our 4 birch trees. We don't know who to reach out for help IF its possible to use some sort of chemical and save our trees. Any recommendations or ideas will be greatly appreciated. Thank you for your services.

Lane County Oregon

1 Response

Some ornamental white birches in Oregon have been infested with beetle-like insects. The bronze birch borer is a wood boring beetle that has been causing scattered problems in birch.
Stressed trees are often most vulnerable to wood borers. You can improve your chances of keeping trees vigorous and healthy by choosing species well-adapted to your site conditions and anticipated irrigation/fertilization levels. To help assure healthy white birches, avoiding planting them in high stress areas, such as near pavement and on higher spots in the landscape. Mulch under the tree, instead of having grass, may help reduce some stress on birches. In addition, be sure to water during dry weather and extreme heat of summer.
If you like birch trees, you have a variety of options for species and varieties of birch that are relatively resistant to bronze birch borers (if those are the primary insect threat in your area).

Here is some information on the Bronze birch borer:
Agrilus anxius

  • Eventually twigs and then branches dieback starting at the
    top of the canopy and progressively working its way down
  • Foliage at top of the canopy first becomes sparse
  • Raised lumps or ridges can be seen on the trunk and branches
  • D-shaped exit holes can eventually be observed on the trunk
    and branches
  • S-shaped galleries can be seen under the bark
  • Preferred hosts are European white birch and white barked Himalayan birch; paper birch, gray birch are also attacked; river birch is rarely infested

Here is a publication you will find useful.

https://www.extension.umn.edu/garden/diagnose/plant/deciduous/birch/leaveswilt.html

Hope this helps!