Our twisted filbert tree developed a disease this year. I'm not sure if it's caused by an insect or a fungus. The dry, dead branches all have black spots on it. Is there anything we can do, or is the tree doomed? A picture is attached. Thanks so much!
Montgomery County Maryland
This looks like eastern filbert blight, a fungal canker disease. All you can do is look for the stromata (fungal structure-raised bumps) and then prune them out one to three feet below where they stop on a branch. Fungicides are not effective in a home landscape. The tree will eventually decline and you will have to consider removal in the future. Take a look at the attached link for more information and mention of a resistant cultivar page 2.