iris borer infestation

[Nancy Coffey]

Hello folks,

I am in the process of digging up all my iris--this could take weeks--to wipe out iris borer. I have found borer in almost every clump. So far they seem to be confined to the leaf and rhizome and I've found every size from very tiny to big fat ones, but they don't seem to have progressed to the brown pupa stage in the soil.

Instead of replanting them, I am putting them in pots without soil for a couple of weeks, to give any that I missed a chance to grow. Then I'll examine them closely again before re-planting. It shouldn't hurt them to be out of the ground in a shady place for that long, should it? I'll give them a light spray with water once in a while if it doesn't rain.

Do you think that this will break the cycle and render my garden borer-free? I am in southern Ontario.

Thanks, Nancy Bowmanville, Ontario, Canada

[Nancy Coffey]

I've had them for years too and have tried to keep them under control but they really got ahead of me. I saw the damage earlier this year but had to wait until they were big enough to locate before trying to kill them.

I'll wash them off well and then apply Ajax, to see if it helps.

In the fall you need to clean up any dead fans and stuff

I do this, but the leaves should be burned or bagged and put out with the garbage and I haven't always done this.

I was concerned about leaving them out of the ground for 2-3 weeks. I think they should be OK but I'd like to hear opinions to the contrary.

Thanks, Nancy

[Nancy Coffey]

I cut them in half with my pruning shears. Same feeling of satisfaction.

But do you know if I can leave the rhizomes out of the ground for a week or so, to see if any more appear?

Nancy