Iris Borers

Someone recently posted a picture of an Iris Borer (can't find the thread right now).

It got me to wondering -- is there any soil treatment or amendment that can be used to prevent Iris Borers?

Some people use Merit. We don't because of the bees.

Is that something that you add to the soil? If so, how could it adversely affect the bees?

Imidacloprid is the active ingredient in Merit. It is sold as a systemic insecticide for plants, shrubs and trees. It is absorbed through the roots and migrates upward to the leaves and stems. Just the opposite to acephate which is applied to the leaves and migrates downward. Acephate has been banned in some states due to high toxicity.

Imidacloprid is one of the better treatments for iris borers notwithstanding problems with insects feeding off the plant pollen.

Try the link below for "all you wanted to know and were afraid to ask" treatment of the subject. I may need to modify the link to get it to work.

http://en.wikipedia.org/wiki/imidacloprid_effects_on_bee_population

This message was edited Aug 21, 2010 7:51 PM

I did the old fashioned way this afternoon. As I took off the old part of the rhyzome this afternoon, a fat borer popped out. Cut it in half with my garden sizzors & felt good about it.

My daughter's irises were devasted by the iris borers last year. She had to dig up every single plant and cut out the bad parts. We have an organic farmer here, bees, beef, etc. and she says it is the systemic poisons that are killing the bees. I have been using Bayer's 2 -in-1 fertilizer to keep the insects out of my roses and brugs. But no more. I will find a safer spray that doesn't stay on the plants.
Systemic fertilizers also endanger hummingbirds who get nectar from the brugs by opening a little hole deep into the trumpet bloom, which means they are also slurping up the systemic fertilizer.