Ugly, foul-smelling seepage from tree wounds is a familiar sight. However, the nature and treatment of this condition still need to be understood. Bacterial wetwood, or "slime flux," is a type of bole rot that afflicts hardwood trees. Sap often accumulates under pressure in affected branches, producing a signature water-soaked appearance.
The disease is associated with numerous bacteria infecting the inner sapwood and outer heartwood. Slime flux generally occurs when a tree has been wounded or suffers from environmental stress. These wounds can be from insects, birds, wind, equipment, frost cracks, pruning wounds, propagation wood, or split crotches. Once the tree is infected, the bacteria will feed on the tree's sap as a nutritional resource.
This causes slimy, water-soaked areas in infected trees' trunks, branches, and roots. Bacterial wetwood is not fatal to trees. However, persistent infection can contribute to a general decline in tree health.
How did this happen to my tree?
The disease cycle begins when bacteria infiltrate the sapwood. The bacteria reside in the sapwood, feeding on the sap. As the bacteria consume the sap, it depletes the oxygen in the heartwood, which produces methane. This process causes the pH levels of the sap in the tree to increase. As the pH rises, the sap ferments and pressure develops in the wood, reaching up to 60 psi, forcing bacterial ooze. The ooze is alcohol based and toxic to new wood. As it exudes from the tree's bark, the ooze kills the cambium near any injuries, preventing them from effectively callusing over. Any plants or grass that are under the tree and get any slime flux liquid on them could also become infected or die.
How to identify:
The first symptom of bacterial wetwood you notice is seeping or bleeding from the wounded tissue. It starts as colorless but changes to white-tan or darker upon exposure to air. Next, a slimy, foul liquid is discharged from the tree and trails down the bark, causing visible staining. Insects are attracted to the liquid upon which they feed. When affected by bacterial wetwood, the branches of younger trees often wilt.
Mature trees may experience reduced foliage and may turn prematurely yellow scorched, and withered. You may also see swelling of the affected trunk or limbs.
Slime flux also has many similarities to virticulum wilt, another condition that may be affecting your trees. It also appears in isolated pockets of sapwood closer to the outside of the tree. Besides all the external signs, you can also observe bacterial wetwood internally. Slime Flux, in some instances, occupies the middle of the tree or "heartwood." If you remove an infected tree, the heartwood will look dark in color compared to the surrounding wood.
How to help your tree:
Treatment of infected trees and limbs includes removing dead limbs in the spring after you notice the first symptoms. Fertilizing the tree may also aid in overcoming adverse effects. Due to the high-pressure nature of the condition, one accepted practice is to drill a hole upward into the infected area and insert a tight-fitting pipe. The pipe must protrude from the bark far enough to prevent dripping on the tree. Drill the hole through the tree within a few inches of the opposite side. Examine the corings to determine the depth of infection. You may find more than one infected area. Drilling the hole and inserting a drain must be preplanned and done quickly because the wood surrounding the fresh hole rapidly expands, thus sealing in the pipe.
Sadly, there is no completely effective remedy or preventative treatment for slime flux. However, you can use the following methods to help alleviate symptoms and manage infections:
When you are planning to plant, choose trees that are disease resistant.
Fertilize and aerate stressed trees to stimulate new healthy growth
Prune away dead or weak branches and any loose or diseased bark. Disinfect tools with 70% rubbing alcohol before and after pruning, and apply clean cuts around the wound to facilitate healing.
Ensure your trees are adequately watered, especially during periods of dry weather.
Apply mulch around the base of susceptible trees to improve soil quality, retain moisture, and moderate soil temperature.
The best thing that you can do to treat slime flux is to prevent it from happening. The best way to do this is to have an arborist inspect your trees at least twice a year. Having an arborist regularly check your trees will ensure that they will identify the problem and get it handled before it damages the tree. You need to act quickly if you have noticed signs of slime flux in your yard. Call an arborist to evaluate your yard for the best solution to keep it as healthy as possible! The sooner, the better, as you do not want this nasty condition to spread to any more of your healthy plants and trees!