Life Cycle: Spores from Tubakia leaf spot overwinter on the twigs and leaves of diseased trees. In the spring the wind and rain cause spores to travel spreading the disease to new hosts.
Damage: Tubakia leaf spot is most common in red oaks but can also be seen in maple, elm and hickory trees. The damage is typically apparent this time of year into early fall and is mostly an aesthetic problem. Spots that appear on leaf veins cause the tissue to die and in extreme cases can result in leaf drop.
Control: The best control is prevention. Ensure trees are not under environmental stress by maintaining proper soil moisture. Clean up debris in the fall to remove spores that may try to overwinter. Chemical treatment is not recommended. (Cynthia Domenghini)