Hello Peter,

You are right, bronze birch borer is a serious pest of birch trees. Read more here: https://extension.psu.edu/bronze-birch-borer#:~:text=The%20bronze%20birch%20borer%20is,and%20cut%2Dleaf%20weeping%20birches.&text=Agrilus%20anxius%20Gory-,The%20bronze%20birch%20borer%20is%20a%20serious%20secondary%20pest%20of,also%20been%20reported%20on%20beech.

However, as you can see in the article, the insect in your picture does not resemble the bronze birch borer. In fact, your picture seems to show the exoskeleton of a cicada larva. The females lay their eggs in slits in twigs of trees which may cause minimal damage to the tree shoots and may not require treatment. Read more here: https://www.canr.msu.edu/news/periodical-cicadas-emerging-should-michigan-fruit-growers-be-concerned

And here: https://www.canr.msu.edu/news/michigan-insects-in-the-garden-season-2-week-1-annual-cicadas

You mention that you have seen no die-back in the crown of the trees which is caused by the bronze birch borer. Also, there would exit D-shaped holes where the adults emerge from the tree in the spring but no exit holes are evident in the pictures.

Before you treat any tree, you need to know if the tree is in need of treatment and what is the agent that is causing the problem.

A submission to MSU Extension’s Plant and Pest Diagnostic Lab will provide you with a more definitive answer. To learn how, go to: https://www.canr.msu.edu/pestid/

A certified arborist can assess your tree. To find an arborist in your area, go to www.treesaregood.org, the website of the International Society of Arboriculture.

Thank you for contacting Ask Extension.