Irises forum: Connection between rot and iris borer?

Views: 407, Replies: 4 » Jump to the end
Name: Mary Anne Jay
Wentworth, NS, Canada (Zone 5a)
Region: Canadian
Image
Raven
Apr 12, 2017 3:26 PM CST
My first iris was Superstition in 2009. I loved it so added several over the next years to about 70 by fall 2014. '09 to '14 saw lots of gorgeous colorful blooms in my gardens. Lots of increases too. I mixed them into my perennial beds. In the winter-2014/2015, we had a lot of ice and snow so, when it was gone, so were about a dozen irises--rotted. Summer of 2015 saw the first iris borer here and loss of some more irises. Last spring, more rot. Last summer, borers. So I wonder if there is a connection? Do borers spread disease or does disease invite borers? I expect more of the same this year since many of my irises have rotted or have increases with rotted grow points. Sadly, I am removing all irises except dwarfs which seem to more resistant to rot/borers.
Name: Jane H.
Kentucky (Zone 6b)
Irises Birds Region: United States of America Region: Kentucky Clematis
Image
janielouy
Apr 12, 2017 4:35 PM CST
Rot generally follows the borer. Too much moisture (rain, freeze and thaw, etc.) also can cause rot. If rot sets in and is not treated with some Comet or bleach type water, it will get worse. I think it could also infect nearby plants if rotten irises are left in the soil. Some irises are more prone to rot and also to borers. But if you had borers once, they will continue to lay eggs and the cycle continues. The best treatment for them is a systemic insecticide that contains imidacloprid which should be listed as the main ingredient.
Name: Mary Anne Jay
Wentworth, NS, Canada (Zone 5a)
Region: Canadian
Image
Raven
Apr 12, 2017 5:08 PM CST
Yes, that is all probably true. Maybe I had the borers before the winter of snow/ice but didn't notice them. I don't want to use chemicals because bees are important in my gardens. Also, many of the chemicals available in the US are banned here. I tried the bleach/comet thing last year to no avail.
There are many pretty plants with fewer problems so I need to make it easier on myself. I will keep a piece of Superstition {it seems to resist the rot} and the shorter ones like Blue Eyed Blonde, What About Me and a few others. They clump up so fast that the rot can't get them all! Sticking tongue out
Name: Jane H.
Kentucky (Zone 6b)
Irises Birds Region: United States of America Region: Kentucky Clematis
Image
janielouy
Apr 12, 2017 7:12 PM CST
There are some treatments that are organic of a sort like nematodes. The old search and squish works too if you can get to them early before they reach the rhizome. There are many good articles with pictures of damage and such on the Internet. People west of the Rockies do not have the borers. Lucky....
Name: Bonnie Sojourner
Harris Brake Lake, Arkansas (Zone 7a)
Magnolia zone
Region: United States of America Region: Arkansas Master Gardener: Arkansas Irises Plant and/or Seed Trader Moon Gardener
Garden Ideas: Master Level Dragonflies Bulbs Garden Art Celebrating Gardening: 2015 Gardens in Buckets
Image
grannysgarden
Apr 12, 2017 8:39 PM CST
I think that any 'wound' in a rhizome makes it possible for disease to enter. I know when I make a cut to separate irises I lay them on a work bench for at least 24 hours in order for the wound to callus over. If a borer gets into a rhizome and leaves an open wound then I expect that would weaken the plant and leave an opening for bacteria to enter. I have not had borers but I think I would attack them aggressively. I would dig the irises up, treat the soil, wash the rhizomes and inspect for damage and kill any critter lurking there. I understand if you get them early they are in the leaves working their way to the rhizome and can be squashed by just mashing the leaves between your thumb and finger.
Who plants a seed beneath the sod and waits for growth believes in God. ~~Unknown

« Garden.org Homepage
« Back to the top
« Forums List
« Irises forum
Only the members of the Members group may reply to this thread.

Member Login:

Username:

Password:

[ Join now ]

Today's site banner is by ge1836 and is called "August Caladiums"