Hi Sherry. I don't have a clue what the little black ant like creatures are or if it indeed them making the holes in the iris rhizomes. I suggest you trap a few of the bugs in a little jar and take a destroyed rhizome to your county extension agents office. They will be able to id the bug and tell you what to treat it with that will not hurt pets. I have never heard of tiny ant like bugs eating rhizomes. It sounds a bit scary to an iris lover. Good luck and let me know what you find out. If it is the ant like creature making holes in the rhizomes see if you can post a photo of it here. Perhaps this is something new we all need to be aware of.
