Gummosis is that sappy, gewy looking stuff that oozes out of the bark of many fruit trees, maples, birches and citrus.
When gummosis strikes a plant it's actually telling you one of many things is going on with your plant. For instance, it may be telling you that your apple has a tree borer. It may be saying that peach is under too much stress from lack of water or too much water.
Gummosis can also be an indication that a condition called flux is coming on and prepare for a viral problem. Or, Gummosis on a plant is no more than a cleaning process or purging of the soil, if you may.
In any case, when your plants ooze with Gummosis take heed to what it is trying to tell you.