Disease

Bacterial wetwood (slime flux)

Several bacteria in the heartwood

Bacteria living in the inner wood build up pressure and push foul-smelling liquid out through cracks and wounds. It is common in elm, cottonwood, poplar, willow and maple, looks bad, and rarely harms the tree.

Signs

• Dark, wet streaks running down the bark from a crack, branch stub or wound.
• A foul, fermented smell; the ooze may froth in summer.
• Bark below the streak stained gray or brown as it dries.

What favors it

Wounds, cracks and old pruning cuts on elm, cottonwood, poplar, willow, maple and mulberry.

Prevention

• Avoid wounds on the trunk.
• Keep the tree well watered; stress makes the flux worse.

Crops it shows up on

Shade & ornamental trees.

Often confused with

Sources

• Bacterial Wetwood or Slime-fluxMontana State University Extension
• Slime FluxUtah State University Extension

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