WSU Extension


Bacterial wetwood (Slime flux) 
Dutch elm disease 
Nectria canker 
Bark beetles 
Elm leaf beetle 
Elm leafminer 
European elm scale 
Spiny elm caterpillar 

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Caption: Elm bacterial wetwood (slime flux)
Photo by: R.S. Byther
Elm : Bacterial wetwood (Slime flux)
(revision date: 4/28/2014)

Wetwood or slime flux is a bacterial infection common in elm and poplar. The infection causes production of large amounts of moisture in the wood of trunks or large branches. The rancid-smelling, often brownish fluid seeps through the bark and is associated with discolored wood and streaks on the bark. Occasionally other symptoms including wilting, yellowing, and dieback may be associated with wetwood in elms. Typically, however, wetwood is primarily an aesthetic concern.
Management Options

Non-Chemical Management
  • Preventing injury to bark and wood may help prevent wetwood.
  • Installing plastic drain tubes to allow the fluid to drip on the ground rather than down the bark may improve the appearance of affected trees.
  • Affected branches can be removed for aesthetic reasons. Cut back to clean, healthy wood.
Select non-chemical management options as your first choice!

Chemical Management

None recommended


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Caption: Elm bacterial wetwood (slime flux)
Photo by: R.S. Byther