Armillaria root rot is a disease of trees and woody plants
Armillaria root rot is a disease of trees and woody plants caused by the fungus species Armillaria. This fungal disease affects more than 200 species of trees, with oaks, elms, and maples being the most susceptible.
Signs and symptoms of Armillaria root rot
The initial symptoms of Armillaria root rot include:
- Stunted leaves
- Reduced tree vigor
- Canopy thinning
As the disease progresses, there will be significant branch dieback, as well as root and heart rot that will compromise the structure of the tree. In the fall, clusters of honey-colored Armillaria mushrooms may grow at the base of infected trees.
Since the fungus absorbs nutrients from the tree’s heartwood, the tree’s wood will turn white, soft, and stringy.
Managing Armillaria root rot
The best way to reduce the chance of infection is to keep your trees healthy and prevent stress. This means proper watering, mulching, and avoiding wounds. When removing a tree with Armillaria root rot, make sure that all stump and root material are destroyed to prevent its spread. Plant trees that are resistant to the fungus, like Kentucky coffee tree, sycamore, and black cherry.