Trees are no stranger to diseases, which can result in white mucus appearing on the bark. This substance can be nothing more than an annoyance or it can be a serious problem that poses a risk to the health of the tree. Once you have identified the cause of the white mucus, treat accordingly and take the necessary precautions to keep it from returning.
Also called bacterial wetwood, slime flux disease attacks various species of trees affecting the bark and center core of the plant. Trees infected with slime flux develop discolored areas on the bark that begin to ooze a white mucus-like substance. As the disease progresses, the leaves begin to wilt, and branch dieback occurs. No chemical treatment options are available. However, you can control small infections by carefully opening the wounds in the bark. This exposes the area to air and helps prevent the fluids created by the disease from building up under the bark.
Caused by the fungal pathogen Sclerotium rolfsii, southern blight causes white, webby mycelium -- filaments produced by the fungus -- that can have a mucus-like appearance and occurs at the base and lower stems of infected plants. Southern blight leads to wilted foliage and dieback, as well as rotting of the lower trunk and crown tissue. Southern blight quickly leads to tree death and is most severe in young trees between 1 and 3 years old. Fungicides containing the active ingredient Flutolanil can help control southern blight. The amount of fungicide used to control this fungal disease varies depending on the type used. For example, one brand of Flutolanil fungicide suggests using 1.5 ounces of the pesticide per 1,000 square feet.
Procerum Root Rot
White ooze occurring within the bottom 3 feet of the tree is a sign of Procerum root rot. This fungal disease affects various species of pine trees, such as white pine (Pinus strobus) -- which grows in U.S. Department of Agriculture plant hardiness zones 3 through 8 -- and Austrian pine (Pinus nigra), which is hardy in USDA zones 4 through 8. Mature foliage droops and begins to turn brown, and girdling cankers develop under the bark. These cankers provide a home for the pine root collar weevil, which can spread the disease to nearby healthy trees. No chemical control is available for Procerum root rot, and control requires removing and destroying infected trees.
Considerations and Prevention
Implementing good care and sanitation practices helps keep tree diseases -- such as those causing white mucus to appear on the bark -- at bay. Remove damaged, dead or diseased branches, twigs and leaves from the tree. When pruning the tree, only cut into healthy wood and sanitize the shears after each cut. Keep the ground around the tree clean and free of leaves, twigs and other plant matter, which can serve as a food source and hiding place for pests. Also, ensure the trees are growing in well-drained soil. Soggy areas lead to fungal diseases and rots.
- Colorado State University Extension: Bacterial Wetwood
- West Virginia University Davis College of Agriculture, Natural Resources & Design: Southern Blight
- The Official Site of the Tennessee Government Department of Agriculture: Yard Tree Health FAQ
- University of Illinois Extension: Common Conifer Diseases of Forests
- Missouri Botanical Garden: Procera Root Rot of White Pine
- Missouri Botanical Garden: Pinus Strobus
- Monrovia: Austrian Pine
- Montana State University Extension: ProStar 70WP
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