Hi Michael. Thank you for contacting ‘Ask Extension” with your questions about the Bronze Birch Borer Beetle. They have definitely become a problem in Oregon. The tell-tale sign of a dying birch tree due to borer is the wilting and dying of foliage starting from the top of the tree, along with D-shaped insect exit holes in the bark. The beetles attack a tree that is injured or has environmental stress.

Birch typically grow in shady, moist environments. When planted in hot, dry environments, the trees can become drought stressed and susceptible to beetle attack. Birch trees that are planted in full sun need more frequent irrigation. Borers are unable to survive in healthy trees. Keep trees vigorous with proper watering, fertilizing, and other cultural practices. Do not prune when adults emerge and seek oviposition sites (late April to mid-July) as the females are attracted to fresh cuts.

Unfortunately, The Whitebarked Himalayan birch (Betula jacquemontii) is listed as susceptible to the borer. Moderately susceptible birch includes gray birch (B. populifolia), whitespire birch (B. platyphylla japonica 'Whitespire'), yellow birch (B. alleghaniensis), sweet birch, black birch, cherry birch (B. lenta), paper birch, white birch and canoe birch (B. papyrifer). Those with low susceptibility (more resistant) include heritage birch, heritage river birch (B. nigra 'Heritage'), river birch and red birch (B. nigra). I can’t be much help in finding a source to purchase trees. We don’t endorse one nursery over another. I recommend you call your favorite nursery and see if they carry a cultivar you are interested in. They may be able to help you locate a source or special order for you. Dancing Oaks Nursery in Monmouth came up in a quick Google search as having several Birch varieties.

I’m including a link to an OSU publication titled: “Homeowner Guide to Managing Bronze Birch Borer in the Upper Klamath Basin” The information there is applicable to the entire state. Figure 7 in that document shows five stages of Birch Tree decline. A tree at level 1 -3 has a good chance of recovery while level 4 is less likely to survive and level 5 is basically dead. Removing trees that are unlikely to survive will disrupt the beetle’s life cycle and reduce the risk to the remaining trees. It’s recommended that you work with a licensed arborist to determine if treatment or tree removal is appropriate.

I hope this helps!

Hi Michael, 

This is just a PS to Deb's message. We're sorry to hear you're still feeling stuck. 

Please know you're not alone in either challenges finding an arborist or difficulties with bronze birch borer. Lovely as birches are, in the climate of the Valley they are extra vulnerable to BBB, especially after last winter's storms took chunks out of many birches. It's one of those problems where there is really not a silver bullet, unfortunately, and other folks with birches have had similar experiences. 

There are relatively few arborists who treat for bronze birch borer in Benton County, and arborists are often overbooked, still catching up after last winter's storm damage. I recently waited 9 months+ to get an arborist to remove a sketchy tree, so I understand your frustration. 

One additional place to check for arborists, if you have not yet done so, is here: https://www.treesaregood.org/findanarborist

Here's wishing you and your birches good luck - and crossing my fingers that right arborist comes out of the woodwork and can make a difference for your trees. 

Kind regards - Elizabeth R., Program Staff