Japanese iris foliage problem

I planted 18 JI's, received through a wholesaler, in fall of 2008. Found this yesterday on six plants and hope someone can tell me what it is and if it needs to be treated. If so, what should I use?

I dug all the suspect plants and will segregate them from all others.

We have not used any insecticides, sprays, Preen, Round Up or chemicals of any sort for any reason back where they grew under the pines. It is not pine sap. Other plants in amongst the six problem plants are not affected at all.

Any help would be appreciated. Thank you.

Pirl, have you contacted and sent your photo to anyone in the JIS? Japanese Iris Society?

John Coble of Ensata is helping me by forwarding the photo to many JI pro's. I would have posted it in the JI Round Robin but Yahoo was giving me grief.

So far there is no answer but I've tossed all suspect plants (not for compost!) and bleached my tools. I'll replant 3 JI's that were part of the afflicted group but not on my property, just to see how well they perform.