University of Manitoba - Faculty of Agricultural & Food Sciences - Slime Flux
Slime Flux

Problem type: Disease

Name of problem: Slime Flux/Bacterial Wetwood

Plant name(s): Many deciduous trees (including apple) and some coniferous trees such as fir, pine and western red cedar

Symptoms / Characteristics:
A sour-smelling, slimy liquid oozes through cracks or wounds in the bark. The slime is usually brown in color and may bubble at the wound sites. Vertical stains may be visible on the surface of the bark. Branch dieback is possible, but tree death rarely occurs. Damage is mainly cosmetic but can be detrimental to the forestry industry due to discoloration, wetness and weakness of lumber. Wood decay is not a concern due to elevated pH (less acidic). This condition, known as bacterial wetwood, may occur in the roots, trunks or branches. It is caused by a soil bacterium that likely enters the tree through the root system, and feeds on components of the wood. As it feeds, it releases odorous fatty acids and gaseous substances. As gas pressure elevates, a dark slimy liquid is forced out of the cracks. Dead water-soaked wood, combined with large populations of bacteria create a distinct foul odor.

Control / Preventions:
There is no control for bacterial wetwood. Using plastic tubes to drain the liquid away from the bark is a possibility but the process of installing the tubes may cause more damage to the tree if an infection should develop. Maintain trees in a healthy condition and prune dead branches when necessary.