Armillaria Root Rot (often called oak root fungus, mushroom root rot or shoestring fungus rot) is caused by a fungus found in the soil which attacks and rots the roots of many plants and trees.
Some of the symptoms of Armillaria Root Rot include the dulling of normal leaf color and the loss of a tree's growing vigor. Often leaves may wilt and turn yellow or brown. Major branches can also die or show excessive signs of wilt. Armillaria Root Rot often causes fruit trees and ornamental trees to slowly die over a period of several growing seasons, but the rate of death can accelerate considerable if the tree is also under insect or nutrient stress.
In fruit trees, a sign of Armillaria Root Rot is often the lack of fruit production on any of the lower branches, with fruit only visible on the upper branches. The roots can also appear to be decaying and the lower trunk and cambium layer of the tree often have brown spots. As the root rot spreads it is also possible to see small white mushrooms or white fan like plaques or strands develop around the base of the tree trunk. Infections are most prevalent in areas of poor drainage or heavy dense soil.
Armillaria Root Rot, if left untreated, can cause rapid tree decline and death. Trees sometimes live for many months in a weakened state, while others will die very quickly.
To control the spread of Armillaria Root Rot, remove dead trees and as much of their roots as possible. If the plant is newly infected, expose its base to air for several inches by removing 3 to 4 inches of soil. In cooler temperatures (before freezing), recover the exposed roots with loose soil.
Armillaria Root Rot should be treated with Agri-Fos Systemic Fungicide foliar spray or Agri-Fos with Pentra-Bark directly on the tree's trunk. If using the foliar spray, repeat every 1 to 2 months and increase the dosage and frequency in more advanced disease cases.