Clarification:
This is occuring on 3 grafts that were done in the last weeks, but it is not occuring on any of the grafts done back in February.

However, another tree (Stayman Winesap on unknown rootstock) also received some later (last 3 wks) grafts, but is not exhibiting the same symptoms.

Could this simply be the sap from the Golden Delicious tree?

Most definitely, the sap is beginning to flow, so that could be what you are seeing. I'm surprised you grafted so late, that is usually done when the trees are dormant. I'd just keep an eye on things to see what happens after the grafts heal.

It sounds like the tree is not happy at all with the brown on the leaves -- that to me usually means a roots problem and the tree is often soon dead. I have never seen dark sap like that except from necrotic (dying) wood.

I don't know what particular disease that is if it is in fact a disease; maybe someone else will know. I don't think there is anything you can do at this point but watch and wait and hope.

Scott

Agree...wait and see.

>> I'm surprised you grafted so late, that is usually done when the trees are dormantNo, grafting is done when the sap flows.

Konrad

You've got fireblight! Either the bacteria was in the scion wood but more likely it over-wintered in your golden delicious tree. The way you can find out is by cutting branches on the golden delicious - if the cut turns orange within 24-48h it's definitely fireblight.

Golden Delicious is definitely prone to fireblight, see http://www.ext.colostate.edu/pubs/Garden/02907.html.

I'd cut the grafts off and try to control the infection in the tree, the ooze will spread the disease to your other trees via insects that feed on the ooze - perhaps the tree is already infected into the roots, in which case you need to replace it.

I've grafted as late as May and June and never had any issue, so it's not the graft timing.

Well, that's not really the news I wanted to hear :( After finally finding some decent pictures of the bacterial ooze from fireblight, that's definitely what it looks like.
http://www.canr.msu.edu/vanburen/fbooze.jpg

I will look to replace it asap, so that I can regraft some of the scions that I'm losing with this tree. These trees are potted. Do I need to completely replace the soil as well?

Now I just need to find a bag of antibiotic...

Stemy:

If the scions on your tree are showing signs of growth, they will not work for re-grafting. Understock can and in fact should be waking up when grafting, but scions need to be dead dormant. It also seems reasonable to assume they may be infected with fireblight by now. Get rid of the whole works.

Don Yellman, Great Falls, VA

Sorry Don. My sentence was not very precise. I have some remaining scions of those other varieties in the fridge. I intend to toss the whole tree and graft clean, dormant scions onto a new tree.