|
Importance - This disease results in persistent, bad-smelling, bleeding cankers on the stem or at the base of many species of hardwoods. Oaks are the most seriously affected species. Incidence is low, but severe quality loss occurs to the infected tree.
Identifying the Cause - The prime wounding agents are insect borers, mechanical injuries, and natural cracks and splits which are rarely observed. Clear sap flowing from the wound becomes colonized with bacteria, darkens, and develops an unpleasant odor. The specific bacteria causing the dark color and odor are rarely identified.
Identifying the Injury - Patches of wet bark having a sour smell are generally the first symptom of this disease. In addition, insects are attracted to the wet area. Often the bark in the area of the slime flux separates from the tree bole and gives a hollow sound when tapped.
|
Elm with active ooze (upper) and discoloration of bark.
Photo by Fred Baker, Utah State University |
