Hello all,

I am seeking advise on iris borers as weather has been strange and the hatching/treatment may be sooner than normal.

I prefer not to use chemicals that may be harmful to humans/animals including bees but 3 years ago I did treat with a bayer (3 in 1 ?) product as someone had suggested it to kill the hatching larva.

Last year I spent a lot of time pinching and digging out/resetting trying to remove iris borers. Unfortunately I have neighbors who do nothing to protect their iris so the moths are still around and seem to seek my iris to lay their eggs!

3 treatments I am curious about and hoping someone has experience to share


Spinosad - how effective and safe is it?

Beneficial insects - lacewings? Others?

Benificial nematodes?


I know the time window to get the larva is very small between hatching and boring into iris and would love to stop them in their tracks this year!


Thanks,
Lisa

First remove all dead leaves (that pull away easily, use scissors if you are inclined to pull) and burn them(dispose permanently). A lot of pests overwinter on them including aphids. Here's a link for further information http://www.missouribotanicalga... Welcome to the forum and good luck.

Thanks Niki

I have already removed dead foliage. I went to your link and it mentions spinosad. Still looking for information on using it from anyone who has tried it.

We have friends who had good luck with the beneficial nemotoads. they are quite temperature specific but safe for other insects.

The 3 in 1 product is made by Bayer Advanced and contains Merit or imidacloprid as the chemical ingredient. I have used it as a drench and there is a 2 in 1 granular kind also by Bayer. Both contain fertilizer. They are easy to use and mostly effective if applied at the right time. That is key and hard to determine. It is likely that you would need to apply it several times at 6 week intervals. I still have some borers but not as many as doing nothing. My neighbor also does not do any chemical treatment so I get the moths from his yard too.

Thanks for your responses. I am still unsure of when to apply anything as temps are not normal this year.
Our temps are in the mid 60s (which is way high for Feb. in Northern KY!). My poor hydrangea is already budding out.

If they hatch early, will they survive or die if temps go back down? I would hate to apply a chemical if nature is wiping out most of them.

Lisa

Once you have temps that stay above freezing for about a week, they will be hatching. It's best to treat them before they start munching too much, as it takes awhile for the chemicals to get into the plant. Once hatched, they seem to survive colder temps.

Ok, I broke down and went ahead and applied the Bayer 3 in 1 drench today to my iris. I will repeat one more time in 6 weeks and hope that is enough. If not, I will be out there pinching leaves again this year.

Lisa

Good luck Lisa, I am in an area of the country where they usually aren't seen. I'll keep an eye out just in case, now is that I don't just have free noIDs.

Here are the instructions I got from ??? somewhere, don't recall. I do this every year and it has pretty much gotten rid of the iris borer in my gardens:

Do a good clean up of the clumps either in the fall after frost hits or next spring (I do both). Next spring, before temps get to 70 degrees but after the irises have started actively growing, treat them with a grub control product containing imidacloprid. Bayer makes a product called Merit Lawn & Grub Control. It works.

Thanks Sue!