The appearance of infection centers in areas of disturbance reflects the insects preference for stressed trees. Once established, the black stain fungus colonizes root and stem sapwood, reducing water uptake and the vertical ascent of sap by clogging water conducting vessels. Once a new infection center is established, spread of the infection from tree to tree occurs through root grafts between healthy and diseased trees. Black stain root disease remains active for a short time period, usually no more than 1 to 3 years after the host tree dies. In recent years, black stain root disease has been detected in many new areas, often causing locally severe damage.
Incidence appears to be steadily increasing.
At the present time, there is no effective cure for already diseased trees. Current management strategies for control of black stain root disease are either preventive or corrective. Preventive management 1. Avoid the use of heavy equipment or vehicles on muddy soil. Avoid road construction within a mile of black stain disease centers.