Wood Rots (fungi): Discoloration, softening, crumbling and disintegration of wood may be caused by a variety of fungi. Prevent damage from fire, insects, machinery and unfavorable environmental situations. Remove diseased trees. Plant trees adapted to the locality. Avoid introducing foreign species of trees unless inspected and approved by forestry personnel.
These rots are usually the result of physical injury and normally don’t kill healthy trees. Treat by removing decaying dead wood and spray with hydrogen peroxide. Don’t cut back into healthy tissue. That only spreads the decay. Don’t paint the area - leave it exposed to air to speed healing.