Indyrose:
yes, its much too early to see iris borer now. They hatch into near-microscopic nasties, and hide deep in the folds of the fan. They will chew their way downwards into the rhizome, but you won't be able to find any until late May at the earliest. They will not hit the rhizome until late June. At least around here.
But since you already dug up your rhizomes, you can give them the bleach bath treatment and replant (soak in 1 part bleach to 10 parts water for about 15 mins). That may or maynot kill them. Watch the leaves for tiny pinholes, then chewmarks and watery marks along the edge of the newer leaves. If you see this you can hunt down the borer inside the fan. But if all you see are just pinholes and very small watermarks/chewmarks, you won't be able to find it. If the chewmarks are quite noticeable and the plant looks under duress, chances are you can find him. At this point it will be from 1/4 to 1 inch long. Keep watching the rhizomes themseves and if you see a hole you can get it out. I use a eyebrow tweezer to extract the bugger and dispense with him. That way you don't have to uproot the iris or do more damage to it.
And remember, good cleanup in the Fall/early Spring followed by Merit is the best treatment
Good luck.
Laetitia

Where do you find Merit? I have not tried it before but want to next time.

Any local garden supply store should have it. Look for the Bayer products. Either the granules for lawn care and grub control which I really don't care for, or the liquid which works better for me. The commercial name is Merit, but the chemical name is imidacloprid. You should be able to ask the salesclerk if they carry the stuff without going crazy amongst the shelves of toxic chemicals.
I found my first Merit at WalMart, by the way, in the lawn care section.
Laetitia