Disease Directory

    Honey Fungus

    Armillaria spp. (A. mellea, A. ostoyae, A. gallica)

    Fungus
    Roots
    Stems
    Whole Plant

    Overview

    See Armillaria Root Rot. The common name refers to the honey-colored mushrooms produced at the base of infected trees in autumn. One of the most widespread and destructive tree diseases worldwide.

    Symptoms

    Clusters of honey-colored mushrooms at tree base in fall. White mycelial fans under bark. Dark rhizomorphs (bootlaces) in soil and under bark. Crown thinning, dieback, and death. Resinosis on conifers.

    Environmental Conditions

    Humid

    Prevention

    Remove stumps and roots of dead trees. Avoid planting susceptible species in known infested areas. Physical root barriers. Maintain plant vigor. Good drainage.

    Management

    Remove infected plants and as much root system as possible. Expose root collar to air. Physical barriers between infected and healthy trees. No effective chemical control. Plant resistant species.