Slime Flux

    Slime Flux

    Many bacterial species

    slime flux

    White slime flux oozing from the bark of a willow (Sherman V. Thomson, Utah State University)

    slime flux

    Slime flux (Utah State University Extension)

    slime flux

    Slime flux in elm (Joseph O'Brien, USDA Forest Service, Bugwood.org)

    Hosts, Symptoms & Signs

    • cottonwoods, ashes, elms and occasionally other trees
    • caused by several species of bacteria
    • two types of slime flux occur in Utah: infections of the heartwood and infections of the bark/cambial tissues
    • general canopy dieback
    • trunk has a wet spot and staining where bacteria are oozing from a fine crack
    • slime flux infections of the cambium can kill trees within 1 - 2 years; trees with heartwood slime flux infections can live for a long time
    • oozing from tree can kill turf or plants below

    Disease Cycle

    • bacteria enter the trunk through small wounds and feed on sap
    • bacteria produce gases, such as carbon dioxide, that build up under the bark, creating pressure
    • eventually the bark will crack and a bacterial ooze is released

    IPM Recommendations

    • Prevent tree stress. Trees stressed from drought, soil compaction, insect feeding or plant pathogens may die within a few years of slime flux symptoms appearing.
    • Keep trees well watered and fertilized.
    • Avoid damaging the trunk to minimize entrance points for bacteria.
    • There is no cure for heartwood slime flux infections.
    • Prune affected branches, etc., of trees with a bark/cambial infection.
    • Pruning requires catching the disease early; advanced stages of cambial infection in the main stem cannot be reasonably removed without damaging the tree.
    • Plant resistant trees.