Hi All, I have a green lace leaf maple that is been in my garden for the past three years. This morning I noticed numerous small, puffy brown blister like growths on the branches of the tree. They tend to scrape off easily and have a powdery white inside and semi rigid outer shell to them. Just curious if anyone knows what this might be, and/or if it is harmful to the tree. If it is harmful, what can be done to cure the problem? I can add pictures to further illustrate the problem if required.
