Early Spring Borer Control

We've not yet hit 70 here (Chicago Suburbs) but came awfully close last week. I wanted to treat my iris beds with imidacloprid over the weekend but the torrential rains nixed that idea. Anyway, I intend to do so this coming weekend. My question: if any borers did manage to hatch would they be killed off by 15-degree F temperatures? We've been in the 40s for a few days now but are promised another arctic blast which will bring temps in the teens a couple nights this week with daytime highs only in the 20s or 30s. I trimmed my established iris foliage close to the ground last fall so hopefully there is minimal debris that could harbor borer eggs.

No cold weather will not kill borer's. I was over at our rental property over the weekend and I was looking at the once small garden there and there were a few iris, I started to clean up and pulled dead mother rhizomes away and there they were in all of their slimy glory. I need to get back over there when the weather breaks and dig up and treat. My inspector recommended treatment for leaf spot when the leaves on the trees start to unfold. If you keep your garden area clean and dispose of any damaged fans and divide for air circulation, your chances of getting those digusting creatures will be at a minium, but treat as soon as you can.

Thanks for your input. I divided just about everything last summer and planted lots of new ones. So everything's pretty clean -- but certainly not exempt from borers. Nasty creatures! I hope I never see another one. Will definitely treat this coming weekend.

Not to change the subject, but may I ask what you use to treat leaf spot, cat?

right now Bonide infuse, but you should alternate with something else from time to time, just like us with medication, they can get use to the chemical.

Thanks, cat.

No Problem.