From my experience, by the time I see the holes, it has already rotted a large portion of the stalk. If this is the case, and you would really be able to FEEL the difference if it is missing a lot from the inside. Then you are most likely going to loose most of, if not all of the stalk. Just cut the head off and you can either cut it up for more pieces, or let it attach as is if you like the size and or shape.
If it is only a small amount of rot, I would open up the hole some, and make sure it gets enough current. This might be enough. Otherwise, cut it at the base, and then trim ALL the bad parts away.