Thanks all, this weekend I am doing the Bayer Advance in all my beds.

tveguy3 said:Vi, Sorry to hear about your borer problem. I had that happen about 4 years ago. I got a product made by Bayer called "Bayer Advanced" It will kill them all within 24 hours. I spread it around the bed and watered it in. The active ingredient in it is Trichlorfon. Then in the spring you should uses another product, a systemic also made by Bayer. It's called Grub Control, and the active ingredient in that is imidacloprid. I didn't dig up everything and replant, as they were well established clumps. I didn't loose any, but some were set back a while. If there are products made by other companies, just make sure they have the same active ingredient. Good luck!

Tom, this is an old post, but I am wondering if you would still recommend using Bayer Advanced this time of year to kill all the borers infesting my iris bed? I know about merit in the spring, and I am considering nematodes, but would bayer advanced kill them now?

Yes, it will....at least after a few days. The "active" in the *Bayer product is "systemic"....which means the plant takes it up, through the roots, making the whole plant "toxic" to insects, when they eat it (a "stomach" poison) I *think* the "Advanced" version of the product also has a "contact" poison included in the mix, to kill those grubs that are in the nearby soil. I use *Bayer Long Season Grub control" (in the liquid form), and all it contains is the "systemic" insecticide.
Every season, I find several leaves that show signs of "borer munching", but.....no borer is present, so, I guess the stuff works