Peach tree goo

I planted four peach trees among other fruit trees during early spring of this year. The trees established nicely, and put on new growth. There was little if any evidence on the peach tree leaves of any disease. The leaves were uniform lush green all season and are just now showing signs of dormancy with leaf color change and leaf shedding even though there are still abundant green leaves on the trees (first picture). I noticed that at the base of all four trees a gelatinous goo that seems to be weeping from the rootstock. Three trees have it worse than the fourth. The goo only weeps from the root stock crown, and I can not find it anywhere else on the trees. In my internet searching, I found that stone fruits can secrete a gelatinous goop when injured, usually from a borer, a canker, or some other mechanical injury. I don't see any evidence of borers. While I wasn't consciously looking for damage on the bare root trees when they arrived and I planted them, they appeared to be sound. Internet searching seems to point what I believe the likely culprit as a canker, specifically Cytospora canker, but if I wipe away the goo I see no evidence of splits in the bark which is usually indicative of a canker. None of my other trees have this symptom.

Has anyone here had this goop on their peach trees, and if so, what if anything did you do? Any examples of it resolving on its own?

I always assume 'goo' means borers on my peaches
When I scrape away the gell there will usually be a tunnel of some sort that I can stick a wire in and try to poke around to kill the larvae.  

The damage is always at the base of the trunk and sometimes under ground slightly....never on the branches like canker might be.

Sometimes I'm lazy and just pour on the wood ashes (now from the local woodfired bakery) against the trunk and hope for the best.  

Our trees are easily replaceable though as they are the same ones I've been starting from seed for years and I always have young ones in line to replace if needed.

Before we moved, we had some trees over 12 years that I just cleaned off any gell at the base, poked any holes with a flexible wire and kept a mound of wood stove ashes piled several inches up the trunk.  I've always meant to ask the new owners if the trees survived after we moved.

Borer damage will eventually kill the tree if left alone.....

EDIT:  ....more specifically, the borer itself, or several will continue tunneling and if there are more every year the damage will be cumulative and the base of the tree too riddled with damage to survive.

Hi James, did you find out what happened to this tree and treat it? How is it now?