Fusarium root disease

This fungus may stay in the stem and roots for years without symptoms until whole tree suddenly dies. The fungus enters through wounds on roots caused by ploughing, herbicides, die-back, frost or water logging. Symptoms appear when tree is subjected to water stress. If stem is cut near soil level, a purplish pink stain is seen. Dry rot will also show at centre of wood if infection has stayed long. This disease does not spread from tree to tree.