Knowledgebase
Birch tree dropping leaves #877630
Asked July 17, 2024, 1:31 PM EDT
Washington County Minnesota
Expert Response
Hi Henrik,
This is a leaf gall, a harmless condition created by tiny insects. Treatment is not recommended, it's ugly but won't hurt the tree.
See this page and the embedded link, which has lots of information:
https://extension.umaine.edu/gardening/2021/11/08/whats-wrong-with-river-birch/
Good luck.