Q: The elm tree in our front yard has a disgusting, brown, slimy mess running down the trunk. As it dries it is leaving a white streak on the bark. What can we do to stop this?
A: Your tree has a bacterial infection called slime flux or wet wood. Many tree species can get this infection, but for some reason, practically every elm tree is affected to some degree. Trees over 10 years old are more likely to get it than younger trees.
The bacteria enter the tree through exposed wounds, such as pruning cuts, damage from lawn mowers, cut roots, storm damage and where two trunks grow together. As the bacteria consume carbohydrates and cellulose, they release gases. The gases create pressure that pushes sap out of the tree trunk. The sap may include some of the bacteria, but on the surface of the trunk, it can become contaminated with yeast and other organisms….