Re: CULT: Iris Borer

At 05:38 PM 7/21/99 -0400, you wrote:
>>>>
Hi Iris Friends
A little advice needed for the novice from those of you unfortunate enough to be experienced with this little devil, the iris borer.
<<<<

Hi, Mary....and I'm sorry to have to welcome you to the "club" of those of us with bored irises.....

This is how I would deal with the problem:

Remove diseased parts/ rotted areas of rhizomes. If the damage is not severe, this can be done by cutting and scraping, without removing all the rhizomes from the ground. If it's really bad, I would remove the plants and salvage the hard, firm white rhizome areas. It's essential to scrape away all soft, rotten, areas. I would treat these scraped and/or removed rhizomes with either a good dusting of powdered bathroom cleanser with chlorine bleach (i.e., Comet, Ajax) or, full-strength liquid bleach. Full strength may be overkill, but it is effective and has not been a problem for me.

Let the scraped/treated areas dry out, if possible in the sun before replacing dirt, or replanting rhizomes. Then, plant, and keep an eye on them, but they should be fine. If I wind up doing this salvage during a wet period, I would use the straight bleach application, and keep special close watch until the weather clears and it's obvious that the rot is halted.

It's generally not really necessary to dig and pitch everything.....but if you've done that....consider it a cartharsis!

As for the soil....I would do nothing now. I probably would replant in a different area if I removed the rhizomes, but not necessarily. BUT I WOULD plan on spraying with Cygon in the spring. Two or better yet, three applications 10 days apart when the foliage is about 6 inches high, or the early tulips start blooming.

If you don't spray....you will have to be extremely vigilant with physical inspection and removal of the beasties. Look for the "frass" they leave down the sides of the rhizomes, and small round holes, and streaky, "wet" appearing foliage. Squish 'em in the fans, or sacrifice that particular fan/rhizome by borer-ectomy if necessary.

But don't panic....and don't get discouraged. Borers CAN be beaten! What is that marine motto.....always vigilant, or something like that? That's what is takes. Please contact me if I can be of further assistance / consolation!

Dorothy Stiefel
Dryden, NY
daf10@cornell.edu
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