Verticillium fungus lives in soil. It can spread via flowing water, wind, or by tools or transplanted plants that have come in contact with the fungus. When the fungus enters the plant’s root system, it blocks the water from circulating throughout the tree.
Verticillium Wilt affects more than 300 plant species including 80 species of trees. Commonly affected tree species include maple and redbud. Conifers are unaffected by the fungus.
The leaves of an infected tree will show yellowing around the edges in mid-summer. Often only one side of the tree exhibits wilting. If an infected branch is cut, it will show discoloration in streaks, bands, or flecks. The discoloration is bright green in maples and magnolias and dark brown in most other species.
To delay the progression of Verticillium wilt, prune affected limbs and water and fertilize the tree. Species may die within one growing season or just exhibit dieback for up to several years. Since the fungus exists in the roots, caring for the tree will not eliminate the fungus and the fungus may live in the soil for several years after the tree dies. Replace the tree with a non-succesptible species to prevent infection. Clean tools that come in contact with infected soil to prevent spreading the fungus to other plants.
Replace trees with a non-susceptible species
|• Tulip tree
• White oak