You might want to check on the Fruits and Orchards forum but chances are, they aren't laying eggs on the vine (the one queen usually does that in their tunnel city). However they may be farming aphids that suck on the vine's new growth and excrete a sweet substance that the ants collect. You might want to spray the vines with a heavy spray of water to dislodge them and perhaps try some insecticidal soap to get rid of any aphids. Then consider some type of bait traps to get rid of the ants.

I have the same problem. These are black ants and they have turned many branches of my vines black with deposits of egg like materials. There is no fruit on these vines yet. How do I remove and prevent them. Washing with water has not helped. They keep returning.

I just don't see where ants would do any damage, I could be wrong. Why not just ignore them and see if they DO do damage, and then take action? :) Arum

I thought so too but the black materials depoist has spread all over the vines and stunted growth. I have used a soap based insecticide followed a day later with water washing. I hope this will be the end.