Hmmm - does not look good to me, but not sure if that is disease or bugs.
@bsharf??
In any event, if it were me, I would rinse off that bulb thoroughly, and then remove any parts that are soft or rotten - it does not actually look rotten to me though. And then I would soak it in a water/peroxide mix for about 15 minutes, then set it on your counter for a couple of days (upside down if possible for the layers to drain) before planting it again - in sterile soil.
