I have only skimmed this thread, so pardon me if I missed something crucial. I just want to hurry to suggest that this is probably a different culprit than the soft rot that typically accompanies warm wet weather and that has the distinctive stench (the one I associate with rotten potatoes--but I'm from Idaho originally). Anyway, what folks are describing here sounds like what I complained about a week or so ago and that seemed to me, from a bit of interweb research, to be botrytis, which is fungal, and if I read correctly, it's typically a cold-season problem. I've dug up a couple of the worst-affected rhizomes, and on a couple of them the mold was apparent around the new increases. The mother rhizomes had become corky. That first day I suspected fungus I bought three different antifungals and sprayed one on all of my irises, since mold spores spread easily. Then I used one of the different antifungals to spray them again yesterday, which I think might have been a day or two earlier than the time recommended (10 days), but Saturday's really the only day I have and I didn't want to wait a whole week. Still too early to be sure of the results, but I'm hopeful that the ones I didn't have to dig completely will pull through. Anyway, if you suspect botrytis, I'd recommend doing some reading about it and acting quickly. Good luck to everyone.