It could be soft rot and not have anything to do with borers. Scrape away as much of the soft as you can.....sprinkle with Comet or Ajax powder, and keep dry. I find a spoon works well for cleaning out soft rot. Once you smell it you will never forget the smell.

Did you get a freeze recently? This may have zapped the budding bud/scape.

Paul and Greg: thank you both for your responses. I'll use a plastic spoon and scoop it out. The foliage seems strong, so I didn't pull the plant up, which was my first impulse.

We have hardly had a freeze all winter! But we did have a hard storm last Sat. with lots of hail which lingered. Could this have done it?

Thanks again.

awfull

I am with Paul in that it most likely is soft rot. Soft rot is caused by a bacteria in the soil that invades the rhizome through a cut or "injury". The most likely source of said "injury" would be the iris borer. Another possibility is that your rhizome may be planted too deep. That also seems to lead to more rot than if it were properly situated in the ground.

I am having a major leaf spot out break. Very frustrating. The early signs made me think Iris borer; and I was kinda expecting a possible borer issue. So I treated for borer with the correct Bayer grub application. What I thought were the early signs of borer were in fact Leaf Spot. I have sprayed anti fungal treatments on them, but I am way behind the curve. Looks like I will have a crappy looking group of plants this season. Will continue to spray, but will have to "chop" the heck out of the fans in the Fall and spraying early next year.

Only one plant so far has been adversely affected by this infection and that is a NoID iris. Some areas are a bit too crowded which I will also attend to in the Fall.

Sorry Greg. Too dry here for leaf spot.

Sorry to hear that, Greg, but that's the best you can do. A good thing to do is a baking soda spray as soon as the leaves get up a couple of inches. 3 tablespoons per gallon of water, along with a little oil for a sticker. It doesn't hurt anything, and I think it helps quite a bit. Then if you do see you're getting leaf spot, go the purchased fungicide route, but it shouldn't be as bad.

Enjoy the flowers, and look past the leaves. And hopefully it won't be as bad as you expect.

My fans that have the issue have alot of "spots" and the leaves of the fans are getting a "dried out light green hue" verses the normal healthy look. Could I have put too much Bayer formula down and this is a result? It has been dry. I put the anti borer down and then fed them 10-10-10 two weeks later.

Going to assume that they need water, but any help with the coloration would be helpful. I will post so pictures tomorrow. Thanks.

Are there any treatments for borers that won't hurt the bees? I've never had borers before this year, and just found a bunch of the big, fat, disgusting things this morning. I wondered why so many of my iris weren't thriving this year, and chalked it up to our sopping wet spring and clay-like river bottom soil. I lost so many of them, it just breaks my heart! I decided to dig up some of my bigger clumps to see if they needed divided, or had rot, or what the issue was, and found so many hollowed-out rhizomes with ugly borers in them. I have tons of iris all through my yard, not in one centralized location, so trying to treat them all is going to be a major undertaking. They are my dearly beloved favorite flowers, though, and I don't think I can bear to lose them!

Any recommendations for me? Is it too late in the season to successfully treat for them? It sounds like most of the experienced people here did it in late spring.

A couple of years ago, I tried to go without treating for borers as I was worried about the bees. Needless to say I had a bad infestation. I found a product produced by Beyer that said it would kill grubs instantly. I got some and treated my irises. It did work, but for the life of me I don't remember the active ingredient. It was differnent then what we use in the spring.

I've been selling some irises and a lady who bought some told me that she uses a 10% bleach solution in the spring, sprays it around each plant and said that she never has a problem with it borers. Any one else ever hear of that working?

The latest info from our local bee-keeping Assc., says that the "merit" DOES show up in bee colony checks, as do several of the systemic fungicides, so it's concluded that it both are present in the nectar, and/or pollen. But, they felt the worst problem is "contact" with the product on the leaves of plants. So, I read this as saying ,treat the soil, without getting the product on the foliage. The Bayer product that I use is a liquid, and I drench the soil, trying to "miss" the leaves. In the past, I have treated in early spring shortly after new growth starts, and then re-treat when the bloom is done( Been doing this for 5-6 years, and have never seen any otherwise un-explainable problem with our hives), but next year, just to be sure, my plan is to start a "drench" program, in early season, with BT(thuricide).to try to catch the borer while he's still in the ground, and make him sick with a fatal disease( google thuricide for info). Then ,when bloom is over, make my usual application of my "merit" systemic insecticide,(to the ground around the plants). I think it can be timed to catch enough growth in the iris to put the insecticide into the plant, before summer dormancy starts. Something else to consider is that any of the powdered insecticides are really bad for bees, as the powder grains are either gathered with the pollen, or attach themselves to the bees legs, and gets carried back to the hive. Insecticide kills bugs, bees are bugs, so you have to use it both sparingly, and in a way to minimize the chance of affecting the "good" bugs. Nematodes have been used by some, and will control borers, but the only chance is to catch the borer between coming out of his pupa stage, and when he crawls up the leaf. And the Nematodes seem awful expensive to me. You have to be pro-active with any chemical borer control, as once they show up, it's kinda' late to do anything but squish them and treat the damage....Arlyn

This article lists a few options for controlling borers. Please note that the company listed in the first section, Garden Shield, appears to be defunct. But, the other two sections have good advice.

http://www.irisgarden.org/bore...

As for personal experience, I burn my iris beds in the winter and have never seen borer here. Whether that's cause and effect or just coincidence is hard to say.

I think burning helps with insects AND disease!...Arlyn

We would not be able to burn here. Fewer problems with borers not that the irises are away from shrubs & trees. We get to know which plants do better even if a borere attacl Found holes in the rhizomes of historic 'The Black Douglas' but no rot. If you look right now & see wet slimy leaves, those are the plants with the borer grub. When weeding in the fall, look for the shiny brown pupae in the soil & smash those.

I'll have to look for pictures of the pupae stage so I know what I'm looking for. Do the soil drenches do anything to the pupae, or only effective in the spring?

The "Merit" only works when it's ingested buy the insect, so until the borer takes his first bite, he's safe( as I understand it, anyway)...Arlyn

Nothing to the pupae. You have to find them, they are brown but shiney & there will be fewer than the grubs as they are canibilistic.

@BookerC1, beneficial nematodes are a non chemical alternative treatment for borers which have been tested to be just as effective or even more so than systemic insecticides. http://www.entomology.wisc.edu...

They are living organisms so they may be a little more finicky about correct application; however, I feel the timing is not as particular as with a systemic insecticide. It's usually applied before the iris flower, but you may be able to put some down now to help things a little bit. It just won't be as effective but sometimes every little bit helps.

My local nursery has nematodes that are on a sponge. They need to be kept refrigerated and used within a week, I believe. You just soak the sponge in a bucket of lukewarm water for a bit, wring the sponge out, and then put that water in a hose end sprayer or drench the iris with it. There are other ways to buy them, however, not only in a sponge. It sounds tedious but it's really just as easy as using a powder.

Since you have borers already in the rhizomes, you can dig the iris out, cut away any affected parts of the rhizome and dip in a bleach solution. I trim the fans down and dunk the whole thing in the bleach water for 15 minutes or so to drown out any borers. I've been completely renovating my garden beds, so I do this any time I divide or move any iris to prevent hitchhikers from moving to another bed. I'm not sure how many iris you have to say whether or not this is feasible to really reduce the borer population this summer, but it's a good general practice.

Then clean the iris foliage up really well in the fall and early spring but do not compost iris foliage.

Some great information here, thank you to all who shared it.