I'd like to know what the pupae look like -- in case I ever run across them. Where could I find a picture?
Cinda -- What a shame that a patch of Iris was lost to them. I've had an entire bed of Irises become infected with them, but I noticed it when the leaves were yellowing. This was many years ago and I didn't know what was wrong, had never heard of Iris borers, and just had a couple of small perimeter beds planted in Iris. I dug one plant up and found the borer in the rhizome. Didn't know what it was, but knew I had a serious problem. I dug up all the Irises in that bed and put the whole plants in buckets of bleach water. Pretty soon there were lots of borers floating on the surface of the water -- dead. I replanted the Irises and they were just fine. Grew new leaves and bloomed the next spring. So they can be saved if the problem is found early enough. And you don't have to worry about replanting in the same soil -- the *problem* was in the rhizome. I think Tom is right about the borers eating each other (gross!) -- but there aren't other borers wandering around in the soil, which I think was your concern.
