Apricot Armillaria Root Rot: A Deadly Threat to Fruit Trees
What is Apricot Armillaria Root Rot?
Apricot armillaria root rot is a serious fungal disease that affects apricot trees and other stone fruit trees. It is caused by the fungus Armillaria mellea, which infects the roots of the tree and spreads through fungal networks to healthy roots of nearby trees. In affected orchards, trees often die in a circular pattern as the fungus spreads outward each season.
Symptoms of Apricot Armillaria Root Rot
Apricot trees with armillaria root rot may show a lack of vigor and will typically die within a year, usually in the spring. The most distinctive signs of the disease are in the roots. Above ground, the symptoms can be similar to other types of root rot:
- Curling and wilting leaves
- Branch dieback
- Dark cankers on large branches
To confirm armillaria root rot, look for these signs:
- Mycelial fans: White, cottony mats that grow between the bark and wood
- Rhizomorphs: Black, stringy fungal filaments that are white and cottony on the inside. You may also see brown mushrooms growing around the base of the affected tree.
Managing Apricot Armillaria Root Rot
Unfortunately, once a tree is infected with armillaria root rot, it cannot be saved. The tree will die and should be removed and destroyed. It is also very difficult to manage an area where the infection has been found. It is nearly impossible to eliminate the fungus from the soil entirely.
To attempt to manage the disease:
- Remove stumps and all large roots from affected trees.
- Avoid planting trees in areas with a history of armillaria root rot or in recently cleared forests.
Preventing Apricot Armillaria Root Rot
The best way to protect your apricot trees from armillaria root rot is to take preventative measures:
- Choose resistant rootstocks: The Marianna 2624 rootstock has some resistance to the fungus, although it is not immune.
- Avoid planting in high-risk areas: Do not plant trees in areas where armillaria root rot has been known to occur.
- Inspect trees regularly: Check your trees for signs of the disease, especially if you have a history of armillaria root rot in your area.
Additional Information
- Armillaria root rot can also affect other types of trees, including oaks, pines, and firs.
- The fungus spreads through root contact or through infected wood chips or sawdust.
- There are no fungicides that can effectively control armillaria root rot.
- Early detection and prevention are key to managing this disease and protecting your apricot trees.
