University of Illinois Extension

University of Illinois Extension

Hort Answers

Bacterial Disease

Many genus and species involved

Wetwood symptoms on tree trunk.
Wetwood symptoms on tree trunk.
3 (1 = rare 5 = annual)
2 (1 = very little damage 5 = plants killed)

The disease affects a wide range of trees, but is most commonly encountered on elm.

Plants Affected
The disease causes an internal pressure which, in turn, causes a waterish material called slime flux to ooze out through wounds in the bark. Slime flux is caustic (very alkaline). Generally, the bark is slowly bleached of its coloring where the slime flux runs down the outer bark. Often there is an unpleasant odor associated with the slime flux for a short period during the growing season.

Life Cycle

There is a complex of bacteria which cause wetwood and little is known about infection and the disease life cycle.

There are no chemical controls at this time for wetwood. Occasionally a plastic pipe may be used to drain the slime flux in order to avoid additional weakening of trunk and branch crotches. Never use a metal pipe since the trees will eventually engulf the pipe. When the tree needs to be removed or trimmed, saws hitting the pipe may be damaged or worse the person using the saw may be injured or killed.

Related Resources
Home, Yard & Garden Pest Guide
Illinois Commercial Landscape and Turfgrass Pest Management Handbook
U of IL - Distance Diagnosis through Digital Imaging
U of IL - Plant Clinic