Tree problem

Asked May 22, 2018, 7:55 PM EDT

Any idea what this is on this oak tree?

Frederick County Maryland possible slime flux oak tree

1 Response

The black area looks like it may be slime flux. The wound allows entry by some form of bacteria which causes the sap in the vascular system to ferment and bubble out of the wound. Typically, it flows down the trunk for some distance and will often encourage the formation of a harmless, but unattractive, black 'sooty mold'. This is usually harmless and no control is necessary. See our website for more information

For an onsite diagnosis you can contact a certified arborist regarding the health of the tree, make sure there is no rot, and the tree is not a hazard. See our link on certified arborists