Q. Can you tell me what happened to the apricot tree?
A. Boy that does not look good. The first assumption people make is borers. This can be true but there are other things that can cause sap to ooze for limbs and the trunk. Stress is one of them particularly in plum. Another is overwatering or rotting of the trunk. So the first thing I would do is pull that mulch away from the trunk and inspect it.
|Sap oozing from limb|
You may have to take a sharp, sterilized knife and cut into the area just an inch below the level of the mulch or soil directly below the sappy area. The wood should be cream colored. The cut does not have to be big, just a knick is enough. Just enough to see the color of the wood or actually just below the bark, the cambium layer.
If the wood has good color then remove a couple of globs of sap and cut the same way just below the sap. This will be a bigger cut, enough to see the wood. Look for any signs of sawdust or sappy sawdust just under the sap. If you see traces of tunneling just below the bark and in this cambium layer then you can conclude it is borer damage.
|During winter, cut into the limb and reveal the borer, removing all loose bark or remove the limb if it is bad enough.|
Lastly watering too often, keeping the soil moist without letting it dry out can also cause sap to bubble to the surface which is really due to stress again most likely.
Pull the mulch away and let it dry out if you think that might be the problem. If borers are the problem, dig them out with a sterile knife and let the tree heal afterwards.