Irises forum: Ants Farming Scale on Irises

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Name: Marilyn
Central California (Zone 9b)
Region: California Bee Lover Butterflies Birds Enjoys or suffers hot summers Composter
Annuals Dog Lover Cat Lover Irises Celebrating Gardening: 2015
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Moiris
Oct 21, 2014 12:22 AM CST
Have any of you ever had scale growing in the folds of the leaves? The ants have moved in and are 'farming' the scale similar to what they do for aphids. They go for the honeydew excreted by the scale. The ants have established colonies among the iris plants.

In other plants you scrape them off, wash with soapy water and sometimes use an insecticide. I have not dug them up yet, but apparently scale can infect the roots too. I've never heard anyone talk about getting scale on their irises.

If you have any experience or advice on the best way to treat this infestation I would love to learn from your experience! I discovered them as it was getting dark. Tomorrow I will investigate further.
Name: Tom
Southern Wisconsin (Zone 5b)
Irises Vegetable Grower Butterflies Region: Wisconsin Keeps Horses Cat Lover
Dog Lover Keeper of Poultry Daylilies Celebrating Gardening: 2015
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tveguy3
Oct 21, 2014 2:54 AM CST
I have never seen it, Take some close up pictures and share with us please! Thanks
I am not afraid of an army of lions led by a sheep; I am afraid of an army of sheep led by a lion. - Alexander the Great
Name: Greg Hodgkinson
Hanover PA (Zone 6b)
Charter ATP Member Irises I was one of the first 300 contributors to the plant database! Region: Pennsylvania Region: Japan Garden Photography
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Misawa77
Oct 21, 2014 4:39 AM CST
This would be a "new" issue for me as well. Never heard of it connected to irises.
South central PA (Zone 6a)
Irises Region: Pennsylvania
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DaveinPA
Oct 21, 2014 6:16 AM CST
Scales tend to be a small problem with most irises, but once established they will overtake the area/plant. Ants do not destroy them. Only when in their "soft" stage do any liquid sprays work to kill them. When in their hard shell stage they are impervious to the sprays. The danger of the sprays is that predatory wasps and ladybugs, which can destroy the scale, are also killed.

Recommendation from http://www.herbs2000.com/flowers/i_pests_dis.htm is to destroy the plant infested with heavy amount of scale. At this stage of the season I would just cut off the affected foliage and put it in the trash, then watch the plant carefully. If only a small amount the scale can be manually crushed or swabbed with a cotton swab dipped in alcohol.
Name: Mary Ann
Kentucky
I was one of the first 300 contributors to the plant database! Region: United States of America Hostas Hummingbirder Daylilies Birds
Irises Keeps Horses Region: Kentucky Farmer Container Gardener Celebrating Gardening: 2015
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Muddymitts
Oct 21, 2014 6:17 AM CST
Nor I. Please share pics when you can.
Thoughts become things -- choose the good ones. ([url=www.tut.com]www.tut.com[/url])
Name: Marilyn
Central California (Zone 9b)
Region: California Bee Lover Butterflies Birds Enjoys or suffers hot summers Composter
Annuals Dog Lover Cat Lover Irises Celebrating Gardening: 2015
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Moiris
Oct 21, 2014 9:50 AM CST
Dave, thanks for the excellent link. It confirmed what I already knew about scale...but with reference to irises. The infested area only has about 40 plants. I don't want to use insecticide, both to protect the beneficial insects and to protect the birds that eat the insects. I'm going to remove the infested leaves and try wiping with alcohol. I know controlling ants is important too so I'll have to research what is the best way to reduce the ant population. When I get out there in a little while I'll take pictures and dig up a few to make sure the roots aren't infested. I really don't want to destroy that many plants!!!! Sad
Name: Arlyn
Whiteside County, Illinois (Zone 5a)
Irises Beekeeper Region: Illinois Celebrating Gardening: 2015
crowrita1
Oct 21, 2014 10:55 AM CST
That is a very interesting link ! Thanks for sharing it, Dave ! I can't say I've ever had this problem, but maybe a closer inspection is called for Shrug! . My "ant problem" is a little different...the darn things want to make their "hills" at the base of the plant....and then the iris is "too deep"in the ground .

Region: California
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UndertheSun
Oct 21, 2014 11:58 AM CST
Thanks for the link Dave! Thumbs up I've never heard of scales on irises either.

Have you tried spraying diluted dish soap on the infected plants?
Name: Marilyn
Central California (Zone 9b)
Region: California Bee Lover Butterflies Birds Enjoys or suffers hot summers Composter
Annuals Dog Lover Cat Lover Irises Celebrating Gardening: 2015
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Moiris
Oct 21, 2014 12:52 PM CST
Ok...I completed the first stage of treatment. I have removed the infested leaves and squished any visible scale. All the leaves went immediately into the covered trash can. Of course I may have missed some of the scale because the they crawl into the folds between the leaves and are hidden. If they have been there awhile the signs are obvious. But if they are new larvae I might have missed them, so I will have to keep a close eye on my plants.

I decided I prefer not to use alcohol for several reasons. First I don't have that much on hand, secondly I don't want to expose myself to that much alcohol. It is absorbed through the skin (and is in most personal care products) and is suspected of being related to immune problems, cancers and parasite infestation.

I plan to try spraying dilute dish soap on the plants...knowing that it won't get into the crevices between leaves...but it may help clean up any exposed eggs, larvae, or adults that I missed when removing the outer leaves.

Here are some photos of what I found:

Signs to look for:

Thumb of 2014-10-21/Moiris/2d3621 Thumb of 2014-10-21/Moiris/601c6b
Brown, chewed/ dried areas where leaf edges intersect, white fuzzy debris.

Thumb of 2014-10-21/Moiris/260948
Ants and soil with white debris at the base of the plants.

Thumb of 2014-10-21/Moiris/19e99f Thumb of 2014-10-21/Moiris/170722
Brown specks and patches with ants present (scales are biting sucking insects so the damage they cause leaves dry brown sections, yellowing and brown spots)



Here is what I found after pulling off the outer leaves that were hiding the scale and their damage:

Thumb of 2014-10-21/Moiris/290281 Thumb of 2014-10-21/Moiris/eff156

Note there are scale insects, white debris, soil, and (not visible in the pictures) the leaves are sticky from the clear honeydew that the scale emit. The honeydew is what the ants eat. Ants will actually protect the scale from being eaten by beneficial insects, which is why it is said that ants 'farm' these insects. This is why it is important to control the ants.

Thumb of 2014-10-21/Moiris/982ba4

The last photo shows a little of the black sooty mold that is a classic symptom of having an infestation of insects that make honeydew (mainly aphids and scale).

More to come later....
Name: Tom
Southern Wisconsin (Zone 5b)
Irises Vegetable Grower Butterflies Region: Wisconsin Keeps Horses Cat Lover
Dog Lover Keeper of Poultry Daylilies Celebrating Gardening: 2015
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tveguy3
Oct 21, 2014 1:00 PM CST
I think I would totally defoliate the affected iris, and then spray with seven spary. I'm not sure if Seven spray or dust would kill it, but it's pretty safe.

Another option would be to dig them up, wash and brush them clean, dip them, and let them dry for a week or so, and then replant in a different area. I'd still take off the foliage.
I am not afraid of an army of lions led by a sheep; I am afraid of an army of sheep led by a lion. - Alexander the Great
Name: Bonnie Sojourner
Harris Brake Lake, Arkansas (Zone 7a)
Magnolia zone
Region: United States of America Region: Arkansas Master Gardener: Arkansas Irises Bulbs Seed Starter
Gardens in Buckets Garden Art Plant and/or Seed Trader Moon Gardener Garden Ideas: Master Level Celebrating Gardening: 2015
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grannysgarden
Oct 21, 2014 1:03 PM CST
Either that or repeat the treatment every other day until the end of the growing season so the few pests that hide in the foliage cannot repopulate them.
I love my garden.... and Jesus, and coffee, and naps.......
Name: Marilyn
Central California (Zone 9b)
Region: California Bee Lover Butterflies Birds Enjoys or suffers hot summers Composter
Annuals Dog Lover Cat Lover Irises Celebrating Gardening: 2015
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Moiris
Oct 21, 2014 1:32 PM CST
I was leaning toward treating them every few days...watching, cleaning, etc. At least for a first step. I still need to dig up a few of the worst ones and see if the scales have infested the roots. I don't want to dig them all up unless other treatments don't work. If I dig them up them I'm pretty much sacrificing any chance of a spring bloom. I don't have any new place to move them to that is prepared...so that's not an option right now either...although in a pinch there is an area I can clean up relatively quickly.

I am fortunate that the weather is nice and my ground will not freeze so I have a little time to work with while I treat and observe the progress. Usually scale is a minor problem...and relatively easy to treat so I'm going to take it step by step rather than taking drastic measures. I consider this a learning experience. I don't think the plants are at risk of being killed as long as I watch them closely and stay on top of it.

I guess we will see.....I'll keep you posted. Lunch break is over now, time to get back out there!
Name: Mary Ann
Kentucky
I was one of the first 300 contributors to the plant database! Region: United States of America Hostas Hummingbirder Daylilies Birds
Irises Keeps Horses Region: Kentucky Farmer Container Gardener Celebrating Gardening: 2015
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Muddymitts
Oct 21, 2014 1:59 PM CST
This is an interesting topic, and I'm learning a lot. Thanks for sharing Marilyn.
Thoughts become things -- choose the good ones. ([url=www.tut.com]www.tut.com[/url])
Name: Marilyn
Central California (Zone 9b)
Region: California Bee Lover Butterflies Birds Enjoys or suffers hot summers Composter
Annuals Dog Lover Cat Lover Irises Celebrating Gardening: 2015
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Moiris
Oct 21, 2014 3:11 PM CST
Welcome! Glad I can contribute! Smiling I have certainly learned a lot from all of the rest of you! Since I have to deal with it anyway I might as well share...and by sharing I get the benefit of everyone's helpful suggestions and links (thanks again Dave I tip my hat to you. ).

Region: California
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UndertheSun
Oct 21, 2014 3:14 PM CST
That is horrible Marilyn! Sad Darn pests! If it's not one thing, then it's another! Grumbling

On a good note....Your irises look happy and healthy and I love your sandy soil! Thumbs up
Name: Marilyn
Central California (Zone 9b)
Region: California Bee Lover Butterflies Birds Enjoys or suffers hot summers Composter
Annuals Dog Lover Cat Lover Irises Celebrating Gardening: 2015
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Moiris
Oct 21, 2014 3:19 PM CST
Oh yes...I love my sandy soil too (even if it means I have to irrigate more often!) ...and yes the pests complicate things...but it's soooo worth the hassle when the irises bloom in spring! Big Grin

Another positive note is that when I was out there I noticed that Daughter Of Stars has 2, going on 3, stalks getting ready to bloom! nodding nodding nodding I'll take photos when they open!
Name: Marilyn
Central California (Zone 9b)
Region: California Bee Lover Butterflies Birds Enjoys or suffers hot summers Composter
Annuals Dog Lover Cat Lover Irises Celebrating Gardening: 2015
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Moiris
Oct 21, 2014 3:24 PM CST
...well my detergent/water spray bottle is refilled...so it's time to get back at it! Thumbs up
Name: Lucy
Hamilton, MA (Zone 6b)
irises
Charter ATP Member Cottage Gardener Enjoys or suffers cold winters Region: United Kingdom Region: Northeast US Irises
Region: United States of America
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irisarian
Oct 21, 2014 3:48 PM CST
Thank you posting the photos. We have never had scale so it is good to know what it looks like. Hope you can get rid of it.
Name: Marilyn
Central California (Zone 9b)
Region: California Bee Lover Butterflies Birds Enjoys or suffers hot summers Composter
Annuals Dog Lover Cat Lover Irises Celebrating Gardening: 2015
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Moiris
Oct 21, 2014 4:54 PM CST
Time for another refill! The good news is that it doesn't look like the scale are attacking the roots. Thumbs up I did discover some hiding around the base of the plant where the foliage was touching the ground, so I am moving the dirt away as I work and drenching the base of the plants thoroughly.

I have removed the mature leaves and left primarily the small tightly connected young leaves. I have not observed any scale between the young leaves so I think this will be ok and leave the plants with enough greenery to continue photosynthesis and growth (this is one of my two peak growing seasons... when the weather cools down in fall, and when it warms up in spring). If I completely defoliate the plants I am concerned that they will be stunted...which I would like to avoid if I can! Sticking tongue out

It has been interesting to observe that certain plants are more susceptible than others...and it may be something to do with the chemistry/flavor of the fluids in the plant that the scale suck...but actually I am beginning to suspect it has more to do with the shape and tightness of the connection between the separate leaves in the fan. There are some plants that seem to be too tight for the scale to thrive, and some that are so open and loose that the scale don't seem to like them. It's the 'in-betweeners" where I seem to be finding the thriving communities of scales!
Thumbs down



Name: Linnea
Southern Maine, border 5b/6a (Zone 5b)
Irises Winter Sowing Plant and/or Seed Trader Permaculture Composter Organic Gardener
Garden Art Daylilies
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Linneaj
Oct 21, 2014 6:38 PM CST
If you use rubber gloves, the alcohol shouldn't bother you. Once upon a time My great grandmother's (went to heaven in the 30's or 40's) jade plant had all kinds of scales. I wiped them off with alcohol, one at a time. My aunt still has the plant.

Dunno if that would be practical for so many plants. What about neem oil?
Don't make fear based decisions.

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