My first iris borer!

OK, so not my first iris borer, but the first one I've ever seen in person. Ten years or so ago, I had a LOT of obvious borer damage in my iris beds, but I never actually managed to find one of the little uglies in action. I knew I had them in substantial numbers, but I must have dug my irises after the borers were already pupating. Never saw a one of them.

Then I started applying imidacloprid every spring, and borer damage virtually disappeared from my iris beds. Every now and then I'd find a rhizome along the outer edge of one of the beds with what appeared to be a borer hole in it, but again I never actually saw a borer.

This spring I applied imidacloprid to two of my beds before running out. I figured after using it for nearly 10 yrs, I must surely have wiped out the borer population in my iris beds, so I felt pretty safe not applying imidacloprid to the one remaining bed.

Over the last couple of weeks, I've been digging, dividing, and replanting all of the MDBs and SDBs in the non-treated bed, and LOW AND BEHOLD I found my first two living borers yesterday with their little heads stuck inside my dinky little rhizomes. As repulsed as I was by them, and as much as I'd prefer to think that I'd never have another borer in my iris beds, I'm actually glad to have finally seen the real live creatures for myself. They're smaller in diameter than I'd expected, and less pink. The head isn't as dark, either. Mostly, though, I'm surprised that they're not pupating yet. I would have expected them to be pupating this late in the season. I wonder, now, if this is normal timing for them or if they're running a couple of weeks late this year because of the prolonged winter and slow, cold spring.

All in all, I'm glad the little buggers finally made a personal appearance. I'm better acquainted with them now - better the enemy you know ... you know? And now I know that it is unwise to skip imidacloprid application in the spring. I won't be making that mistake again.

And now, (previously) alive and in person ... our nemesis, the iris borer ...

pupae are brown. anyone else with irises near you? Could have been moved from there as you know. At least no one says "oh, how cute".

My nearest neighbor is more than a mile away as the crow flies, and she doesn't grow any irises. However, Iris versicolor does grow native here in the swamp bordering my hayfield, and versicolor is a natural diet of the iris borer.

Laurie

Oh, how cu... I mean, how completely disgusting. ;-) I know what you mean about finally spotting a hidden enemy. I trust that one met an early demise after his photo op?

And any friends that it might have. versicolor would do it.

Funny thing about the photo. I dug hundreds of iris clumps, and when I came across the first borer, I was so amazed and disgusted that I smooshed it with a rubber mallet immediately. Just as immediately, I kicked myself for not taking a pic of it first. I've been wanting a good pic of an iris borer to put on my website, so I was pretty irritated that my killer instincts got the best of me before I could grab my camera.

I was actually hoping I'd find another borer. Within an hour, borer number two appeared in a different clump. He was the model for the photo ... before he met his maker under the mallet.

Laurie

Best source for imidacloprid? I saw my first borer yesterday.

I wrote an article last spring with some information on borer control... got some helpful input from Laurie & Anita, too! (Thanks!) There are several brands/sources available, but check the label to see that the concentration is at least 0.2%.

Here's the link to the article: http://davesgarden.com/guides/articles/view/832/

Wow, beautiful batiks.

Mittsy,

You won't find imidacloprid here. It's banned in NYS due to it's toxicity to honey bees.

I'd like to include a link about that in my article above... the only information I could find was that imidacloprid had been classified as "restricted use" (strict guidelines for application, cleanup, etc) for greenhouses and nurseries, particularly in the area around Long Island due to the porous nature of the soil there (groundwater contamination was the big concern). I wasn't able to find out if it had been banned for sale to homeowners, so I assumed it was still available. ?

I did give several other suggestions for reducing and controlling borers -- imidacloprid is not the only option. :-)

Imidacloprid is usually marketed in lawn grub control granules by several different manufacturers. Bayer markets one, as does Scott's, I believe.

Imidacloprid's toxicity to honey bees is debatable. Some studies have demonstrated no toxicity to bees at all, while others seem to indicate a toxicity problem. NYS has apparently taken a stand in favor of "better safe than sorry".

Laurie

I included links to some of the honey bee toxicity debate at the bottom of that article. I didn't know that NYS had officially banned imidacloprid, though... entirely? I've been googling for the past 15 minutes and can't figure it out.

Sorry, I don't want to turn this thread into a pesticide toxicity debate, but if anybody could link me to a current info source on the status of imidacloprid in NYS, I'd appreciate it! (I try to keep links updated on older articles, because I figure people still find them when searching or refer back to them.)

I don't want to turn this thread inty a pesticide debate, either, and I'm all for using pesticides responsibly.

I don't know of any internet links, Jill. I tried to buy Merit one time a few years ago, and was told by local stores, Lowes, Home Depot, etc that the use of Imidacloprid was banned in NYS. I then tried to buy it on the internet and was not allowed to, as I lived in NYS. I then contacted my rep at Cornell, and was told it had been banned first in the counties around Long Island, and then upstate due to it's toxicity to honeybees, and that it had been responsible for killing off honeybees in France, I think it was. He also said they were finding quite a bit of trace Imidacloprid in the drinking water on Long Island.. I spoke with Pirl at the time, and she also said she had found out it had been banned, and she lives on Long Island.

Now this was a couple of years ago, and things change, so I hope ny info is not outdated. I will have to check local stores, once again for Imidacloprid.

And in answer to Mittsy's question, I understand Orthonex works quite well at getting rid of borers also.This from Currier McEwens book on JIs. I haven't had a borer yet, but am expecting one soon, after getting irises from all over.

Polly, I doubt if you'd introduce borers from someone else's garden or nursery. They're darn difficult to miss. Just check your rzs for large holes before you plant.

Hmm, I amend that statement. If you receive irises early in the season while borers are still in the leaf fans, I suppose you could miss them easily enough.

Laurie

I was thinking more the clumps of beardless, Laurie. I do inspect them pretty well, but some of the clumps of pseudatas, for ex., are pretty big. I realize they're not as big a problem on the beardless, but can still be on them. I guess the pseudatas especially.

And I did get some bearded trades in the spring, so that's good advice. Thanks.

Thanks, Polly! I'll keep looking for a link, and I'll at least see about adding a footnote about the ban. I did just now find one publication from 2004 indicating that agricultural & professional products containing imidicloprid had been "restricted" (use by liscensed professionals under strict guidelines), and home use products such as the Bayer Season Long Grub Control were under review with the idea that their distribution/use would be restricted (banned in several NY counties).

I think cleaning up the foliage goes a long way toward controlling borer populations, also.

You're welcome Jill.

Maybe restiricted is correct. I am not certified in pesticide usage, so even having a nursery, I would still not be able to buy it if it was restricted, so that may be the case, and it may not have actually been banned.

Critter, if you want a definitive answer on imidacloprid in NYS, contact the NYS Dept of Ag. I'm sure they can clarify the current regulations and restrictions.

I would like to hear the answer if you do.

I can feel those borers coming. I think they're flying around Hannibal, or crawling around, as we speak.

Laurie, good suggestion -- thanks! I haven't been having much luck so far navigating their website. A phone call might clear things up. :-)

I sent an email via their "contact us" button. I'll post when I hear something, and I'll update the article footnotes, too.

Thanks I'll continue to watch and learn.

Well, I got a reply telling me to contact the environmental department. I did find a listing of currently registered products -- meaning those permitted to be sold & used in the state of NY -- and imidacloprid seems to still be on the list, with some restrictions on some products for the Long Island area. It could be though that it's "restricted" to use by licensed professionals and thus not available to Joe Homeowner shopping at HD.

It also could have changed since I tried to get it. Especially if, as Laurie said, there was controversy about whether or not it killed the honey bees.

Maybe Mittsy can check locally for us, if she was going to get some anyway.

But apparently it doesn't help now, right? It needs to be used in the very early spring?

Right... about the time you see forsythias start to bud out.

That's usually about the time the last 4 ft of snow is on the ground in the iris beds, LOL.

This is just one of many articles on imidacloprid. I chose it because it has quite a few related links in the article. As Laurie stated, the concern over imidacloprid is debatable. Let your conscience and good common sense be your guide.

http://www.newmediaexplorer.org/sepp/2003/11/26/millions_of_bees_dead_bayers_gaucho_blamed.htm

I should have included this link in my last post. It's more specific about the ban of Imidacloprid in New York. You folks in New York need to take a close look at the second paragraph. This may be old news, (not sure) but it could have serious consequences on what pesticides can be used on your garden.

http://answers.yahoo.com/question/index?qid=1006042407085

I think later on, and Laurie might know more about this, that they determined it was a mite that was causing the honeybees death.

We sure have a ton of them around this year, though.

It's been quite a while since I read any of the reports on the potential connection between honeybee demise and imidacloprid. I just remember having the impression that a lot of unsubstantiated claims and suppositions were being made on both sides of the debate. I do hope that research is ongoing so that it can be determined with clarity whether or not imidacloprid poses significant risk to honeybees.

Is there up to date material on using nematodes to fight borer. We don't have a local verswicolor patch to keep renewing borer although we have a couple of "tame" versis in the garden & one "wild" one from SIGNA seed from sent in from Maine. Since there isn't a renewable patch we have fought it with physical observation and disyston 2% granuales around the plant which has been attacked. They are applied on the soil, then watered in. A chemist friend was horrified saying how toxic the granuales are, but the advantage is that the application is only on an affected plant rather than sprayed on the garden. My spelling seems off, but the ideas are there.

Imidacloprid granules are applied the same way, though they're useless if applied AFTER borer damage is noticed. Imidacloprid must be applied very early in the spring when irises are just breaking winter dormancy because it is only effective against new borer hatchlings. Once the borers have fed for a while and gained size, Imidacloprid is no longer lethal to them. Fortunately, one application of Imidacloprid has about a 6 month efficacy period (if I remember correctly), so one early spring application lasts all season.

Try www.irisgarden.org/borer.

Oh yuck! I think I just found my first three iris borers - only they don't look like Laurie's - they're big and FAT and red. (No they're not earthworms and I guess they must have had a really good meal). Found them in the soil while digging up my sick looking irises. Is this just the next stage of their life or are there different varieties - or am I mistaken? Whatever they are, don't think I've seen them before. And Laurie, I think the sandlike stuff I found in the middle of the base of the iris leaves could be their larvae, because I found identical looking stuff inside some of the eaten out rhizomes.

No, the borers that eat the rhizomes ARE the larvae. They are the larvae of the borer moth. Fat and red doesn't sound like iris borers. As in my pic, borers are pinkish with dark heads. Once they have eaten their fill, they go into the surrounding soil and pupate in dark brown, torpedo shaped pupae that I think are about 1/2" long. There is no fat, red stage. I think you've got something else wandering around your iris beds. Perhaps just opportunistic rot feeders that were attracted to your rotting rhizomes. That doesn't mean that you don't also have borers. It just means that there's something else down there, as well.

Laurie

Whew!!! Thanks, Laurie. But I sure do wonder what they are. If I find another, will save it and take a picture.