Iris borer

So now, how do you protect your tall bearded Iris from being destroyed by the borer.

In days gone by, we might have sprayed the rhizomes with rotenone or pyrethrum but now with the ban on pesticides, we need to find alternative methods. Some of us chose not to use pesticides in the past and used preventative methods. The best thing to do is simply to clean up your Iris stands once the Irises have finished their blooming.

In the Fall, you need to cut off the dead leaves (give the plants a mohawk style haircut) throw the leaves in the garbage, not the compost, as the leaves can harbour insect eggs. You could even dig up the plants, cut out old sections, divide the rhizomes and replant. You might even move the stand to a different part of the garden.

During the course of the year, I also examine the leaves and visible parts of the rhizome to try to safeguard the plants. If I see a hole in a leaf, I squeeze around the area in the leaf to kill any borer that is active in the plant. I have even taken a thin wire and run it down as far as I can into the hole to detroy any borer at work in the plant.