I would think that's often the case too. Although I was thinking that it could possibly be due to an injury to the rhizome as well. Some of the rot I cleaned off this year was not around the base of the fan, but on old leaf scars further down. That was identified as probably Mustard Seed fungus and may present itself differently than the more common crown rot. I haven't had as much experience with rot as some of you, so I'll leave it to those who know more.
