This week we have seen and heard of several oak trees with blister-like growths and deformities on leaves. This disease is called oak leaf blister and it is caused by a fungus named Taphrina caerulescens.
If this description sounds familiar and you've seen it on your oaks, there's no need to panic. Oak leaf blister might make trees look sick, but this disease will not impact the overall health of trees. There is no need to spray or treat your trees. Instead, promote general tree health by adequate watering and fertilization. Vigorous trees will be less prone to severe oak leaf blister infections.
Oak leaf blister causes light green, raised areas on upper leaf surface.
There may be several oak leaf blisters on each leaf.
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on May 16, 2012. The information contained within may not be the most current and accurate depending on when it is accessed.