what's wrong with my iris?? HELP......

[buddy110]

Can anyone help me with m,y iris? Herte are some pictures

https://s234.photobucket.com/albums/ee286/Brucepeter/?action=view&current=DSC00484.jpg

https://s234.photobucket.com/albums/ee286/Brucepeter/?action=view&current=DSC00482.jpg

Thanks in advance

bruce

[TheLorax]

They look absolutely horrible, you should dig them all up and send them to me!

Actually, they don't look that bad. You're probably panicking thinking you've got tospovirus but I don't see any evidence of that. Looks an awful lot to me as if you really should dig them up and amend the soil though. Looks very dry and compacted in that bed.

Also too, iris bulbs sorta grow on the top of the soil like what you photographed so when you re-plant them, follow your own photographs for appropriate planting depth. This will give you a good opportunity to divide some of the others to spread them out in that bed. Then water them every week it doesn't rain. Other than that, don't trim them back when they start looking ratty after they've finished blooming. Leave them be until the first snowflakes start hitting the ground and then trim them down to around 6".

They really look fine to me. A little stressed but fine. They'll benefit from having a lot of bags of compost worked in to the ground. To that I always add corn gluten meal from the animal feed store (cheap). Lately I've been adding coffee grounds too. See if those scalded looking straw colored leaves and browning leaf tips don't stop from appearing on your plants after you amend the soil and loosen it up a little bit and begin a watering regime.

[buddy110]

Thanks. I guess the pictures aren't showing the whole thing. I have four patches of iris. Two are producing and 2 are the pictures I posted. The flower stalks have fallen over and the flowers aren't blooming. The leaves are burning up they are small and not producing flowers

Below is a producing patch right next to the non producing one. Strange huh?

https://s234.photobucket.com/albums/ee286/Brucepeter/?action=view&current=DSC00481-1.jpg

The soil is pretty good really. Trace of nitrogen, ph 6.8, high phosphorus and medium potash. Not really clay not to much sand.

I can transplant them and amend the soil NP. But I wonder if it's a fungus or something.

Thanks for the help

[TheLorax]

There's an iris borer out there but I enlarged your photos before I posted and looked for the tell tale signs of that and couldn't find them. Doesn't mean the signs aren't there but I couldn't see them. I then looked at the proximity to that retaining wall wondering about radiant heat and didn't think that would be an issue.

I saw the other photos of the other patches of iris right next to that fraternity paddle photo (which made me laugh being as how I'm a parent of boys) and thoughts of chemical drift came to mind but I don't think so.

Now, here's my problem, "But I wonder if it's a fungus or something". Usually the minute the gardener who is actually growing the plants makes a comment like that, their little voice telling them something is wrong is normally correct 9x out of 10. So, how about digging up some of the worst iris and spreading the rhizomes out to examine as well as taking a few close up photos of the rhizomes to share. Then take more close up photos of the leaves of some of the other iris that are exhibiting that same straw colored dried out look.

Let's see if the people growing iris out in the forums can get to the root (pun intended) of your problem otherwise you'll need to consider taking a whole plant in to your extension office or sending a sample in to Cornell.

[buddy110]

Thanks, I will do tomorrow morning!

[ahughes798]

The only tell-tale sign I ever see of root borer is when my irises stop producing flowers. I've never seen the streaks in the leaves, etc. Dig 'em in early august and have a look at what's happening. You'll know right away if it's borers.

[buddy110]

ok, yook some pictures.
There are practically no roots at all. There are alos small holes on the bottom of one of the completely dead crowns.

https://s234.photobucket.com/albums/ee286/Brucepeter/?action=view&current=DSC00518.jpg

https://s234.photobucket.com/albums/ee286/Brucepeter/?action=view&current=DSC00518.jpg

https://s234.photobucket.com/albums/ee286/Brucepeter/?action=view&current=DSC00514.jpg

https://s234.photobucket.com/albums/ee286/Brucepeter/?action=view&current=DSC00513.jpg

https://s234.photobucket.com/albums/ee286/Brucepeter/?action=view&current=DSC00515.jpg

https://s234.photobucket.com/albums/ee286/Brucepeter/?action=view&current=DSC00516.jpg

[TheLorax]

The few rhizomes I've seen that have been attacked by borers were hollowed out for lack of a better description. Sure looks like that's what you're dealing with.

The third photo reminds me of iris borer damage. The first and second photos could be last year's damage before they moved on their merry way to other plants.

You're too late to even consider an insecticide of any type (timing is way off) but you're not too late for nematodes.

Here ya go-
https://www.extension.umn.edu/projects/yardandgarden/ygbriefs/e122irisborer.html
The species of nematodes are listed out in the above article.

Don't order anything yet until the other THG member weighs in though please.

[buddy110]

Thanks lorax. I'll get to work!

[ahughes798]

Yep, you have iris borers.

Good lord, I hate them.

[buddy110]

I found this too. It seems pretty like a thourough approach
https://renegadegardener.com/content/49irisborer.htm

[buddy110]

I dug up two complete patches today. The first patch ( the worst of them) I did find a pink catepiler inside one of the rhizomes. However most seemed clean with no borers present. The roots are 90% rotted away as shown in the pictures. I'm not so sure this is in fact borer damage at least to the bulk of them. I cut a few up and looked for the little buggers but I did not find any. Most of the rhizomes are firm and seem in good shape.

Any other ideas?

Thanks folks for all your help

[TheLorax]

Iris borers look like hairless pink caterpillars.

[buddy110]

Iris borers look like hairless pink caterpillars.

I know, but shouldn't I have foun them in more than one crown? I would have thought I'd find them everywhere, I didn't

[TheLorax]

Not necessarily.

Found a decent link to describe the life cycle to you-
https://www.irisgarden.org/basicborer.html

https://www.entomology.wisc.edu/mbcn/land504.html
excerpt from above-

Research conducted at the University of Maryland indicates that entomopathogenic nematodes can control iris borer as well or better than the chemical alternatives.

Nematodes in this study were effective because they were applied properly. Application was delayed until soil temperature was above 50°F when nematodes are most active. Enough water was applied (1 quart/ft2) to allow the nematodes to swim close enough to the pest so that they were within their effective hunting range. Finally, the pest was in the larval stage so that the infective juvenile nematodes could enter the pest through the spiracles or anus and colonize them with insect-killing bacteria. Individuals seeking to try biological control for the first time are likely to find success with iris borer if they are given the correct guidelines.

Nematodes! Go for Steinernema carpocapsae. If you only saw one caterpillar thingie, chances are good some may still be in the larval stage which means you might have a window of opportunity to begin control right now. You will have to treat next spring because your timing is off and you won't get them all.

Something else I found while poking around for you that might be of interest and worth researching-
https://www.irisgarden.org/boreralternatives.html

Here are two sources for the nematodes should you be interested in trying this route sort of late in the season-
https://www.buglogical.com/beneficialNematodes_control_soilDwellingPests/beneficialNematodes.asp
https://www.naturalinsectcontrol.com/catalogue/getprod.cgi?2210C

If it was me and those were my iris, I would definitely go the nematode route next spring when the leaves are starting active growth but before they begin to bloom. Timing is everything.

[buddy110]

Thanks again. I ordered some for now and I'll retreat next spring. I also have some chemical so I'm attacking it both ways!

[TheLorax]

You probably shouldn't use the Cygon product at this time of year as to the best of my knowledge it won't be all that effective. Actually, you shouldn't use the Cygon product if it is your intent to use nematodes. Your chemical may very well kill the nematodes.

You could try the GardenShield product but I don't know much about it other than what I read.

I don't know if you were aware of this or not but research out there indicates the Steinernema carpocapsae is 100% effective if applications are applied properly. Early next spring would be the best time. I think you will have this problem cleared up by this time next year.

Also too, those nematodes are live. You will need to ask if your product will still be good to go next spring. I find when using biological controls that 6 months is about it for the product and then you have to re-order.

[buddy110]

You probably shouldn't use the Cygon product at this time of year as to the best of my knowledge it won't be all that effective. Actually, you shouldn't use the Cygon product if it is your intent to use nematodes. Your chemical may very well kill the nematodes.

You could try the GardenShield product but I don't know much about it other than what I read.

I don't know if you were aware of this or not but research out there indicates the Steinernema carpocapsae is 100% effective if applications are applied properly. Early next spring would be the best time. I think you will have this problem cleared up by this time next year.

Also too, those nematodes are live. You will need to ask if your product will still be good to go next spring. I find when using biological controls that 6 months is about it for the product and then you have to re-order.

It's funny you would say that. I was thinking about that last night. But I figured theuy would last if kept refrigerated. I'll call them this morning and check on that.

Thanks so much for all your help, Lorax!!