It is the time of the year when wetwood or slime flux might be observed on infected trees. This condition is common in poplar and elm but can also be found in maple, birch, oak, sycamore, ash, linden, redbud, fir, beech, willow, cherry, plum, butternut, walnut, hickory, apple, cottonwood, aspen, and mulberry.
Bacteria enter through open wounds from boring insects, mechanical damage, or poor pruning.
The build-up of bacterial populations within the tree causes fermentation of tissues resulting in internal gas pressure of up to sixty pounds per square inch. Foul-smelling, slimy liquid then exudes out of bark cracks. Most of these cracks appear during the winter months possibly due to the inability of affected wood tissues to withstand temperature fluctuations. There is no known effective control for slime flux. Inserting drain tubes around the affected area is no longer recommended.