White Burch trees

Asked April 14, 2020, 4:59 PM EDT

I planted these five trees 3 years and they have been growing fine. Right now three are all green and seem fine.two of them are all brown and are not doing good. Local nursery said you might be able to help. They think there is some beetle that is in the dirt killing them. Any help would be great.

Oregon

3 Responses

The problem is likely the birch tree borer. The adult is a copper/bronze colored slender beetle. The larvae, which does the damage, are unseen, feeding on the vascular tissue under the bark. The Bronze Birch Borer typically attacks trees which are already stressed or in decline. A birch infested with Bronze Birch Borer will start showing dieback in the crown, increasing in severity as the infestation continues, often leading to death of the tree. In later stages of infestation, the trunk will show D-shaped, rust-stained exit holes and may also have swollen extrusions under the bark where the tree tried to grow over larval galleries.

BBB cannot kill healthy trees and is most likely to attack old, stressed, or drought-stricken trees. While many homeowners may not place a high priority on watering mature trees, this can be a key strategy for preventing BBB damage in dry areas. Birch trees tend to be shallow-rooted and respond well to watering. Removing trees too damaged to recover disrupts the BBB life cycle and can slow the spread of the pest. Removal is also the only option for trees with heavy infestation.

Here are a couple of publications to check out:

http://oregonstate.edu/dept/nurspest/bronze_birch_borer.htm

https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/em9189.pdf

Hope this helps!

Should I cut down the two bad ones to prevent the other three from be exposed??

Yes. If you see that your trees have died or may be heavily infested with the borers, the best option Is to remove them from your landscape.