Bronze birch borer


Can I treat bronze birch borer on a silver birch tree myself?


Thank you for your question.

The bronze birch borer  can be a major pest to all species of birch and is known to occur throughout the range of birch in Canada. This insect generally attacks weakened or injured trees and targets very exposed trees, with the white bark birch being most susceptible.  The adult borer is a slender, bronze 12 mm in length beetle that emerges from June through to August.  It emerges out of holes in the bark and feeds on leaves.

The long white larvae develop over 2 years and make long winding tunnels just under the bark.  Yellowing and thinning of foliage can indicate early signs of bronze birch borer disease.

We would recommend good cultural practices for treating and keeping your tree  healthy.

If the tree is lacking in nutrients, fertilize and water well, especially during any dry periods.  You could also consider mulching the tree to help maintain moisture and assist with keeping soil temperatures moderate.   It is not recommended to prune in spring once the leaves have branched out.  Adult birch borers are attracted to fresh pruning sites so best to prune any ailing or dead branches in the fall when the adult borers are less active.  Composting any of the pruned branches is not recommended.

We do not recommended any chemical treatments.  However, if you still require assistance with getting rid of these insects, we suggest you consider contacting a certified arborist or Landscape Ontario who can recommend an arborist in your area.

Both the Morton Arboretum and Natural Resources Canada have good information on the life cycle and treatment of the Bronze Birch Borer and I have included the links below:


May 8, 2021