This disease causes the bases of leaf fans to become soft and slimy. The rhizomes will soften and become mushy. This disease is accompanied by a very foul smell. In less severe cases remove the infected fans and scrape away the soft rhizome tissue. Treat the exposed firm tissue with sulfur or chlorine powder to help disinfect this area.
Crown rot is another disease that can affect iris rhizomes.
There will be a softening of rhizomes, similar to bacterial soft rot, and small round cream to tan spots on the leaf bases. This disease is not accompanied by the foul smell. Remove and destroy seriously infected plants. Iris scorch is a non-infectious disease. Little is known about the cause.