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How to Manage Pests

Pests in Gardens and Landscapes

Wetwood or Slime flux

Wetwood is caused by several species of bacteria; yeast organisms may also be involved. Wetwood is especially common in elm and poplar, but affects many other plants including box elder, hemlock, magnolia, maple, and oak. Affected trees have stained areas of wood that exude fluid. Usually trees about 10 years of age or older exhibit symptoms. Foliage wilt and branch dieback can occur on severely infected trees. Although it can be unsightly, affected wood may be as strong as healthy wood.

Identification

Solutions

Prevent wetwood bacteria and yeasts from infecting trees by avoiding injuries to bark and wood. Control wetwood infections when they are small by opening wounds so they are exposed to the air and liquids do not accumulate; avoid making large wounds. To reduce the spread of bacteria and yeasts in an infected tree, drill a 0.25-inch hole several inches long until fluid begins flowing, then install a copper tube to drain excess fluid and release the pressure of gasses that form in infected wood. Don't insert the tube so far into the hole that the inside end becomes plugged. Leave the outside end of the tube protruding so that liquid drains away from the infected bark area. Check the tube opening regularly and clear it if it becomes plugged. Do not weaken the tree's structure by drilling drain holes at branch crotches.

Wetwood infection
Wetwood infection causes stained wood


Statewide IPM Program, Agriculture and Natural Resources, University of California
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For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See How to manage pests, or in the U.S., contact your local Cooperative Extension office for assistance. /PMG/GARDEN/PLANTS/DISEASES/wetwoodsslime.html revised: March 5, 2009. Contact webmaster.