Verticillium Wilt - https://mailchi.mp/unl.edu/nebraskas-forest-health-report-july-2019
Symptoms of Verticillium wilt are now becoming apparent in infected trees in the form of wilting and dying branches. This is most often seen in species of maple, elm, catalpa, and magnolia. The disease is caused by a fungal pathogen that lies dormant in the soil, often in pockets. If roots of a susceptible tree run into this fungus, it may infect the plant, often causing dieback on branches. Certain infections may also be chronic and lead to a slow dieback. Infested tree tissue may or may not show staining of the vascular tissues.
Unfortunately, there is no cure for this disease. Trees showing symptoms can be pruned back and properly mulched and watered to improve tree health. Remember to sterilize all tools used for pruning after each cut. If the tree dies or removal is desired, it is advised to plant a resistant species in its place. Resistant species include oak, willow, honeylocust, walnut, and linden among others.