June - is this crown rot? - No. Southern Blight

[jerryshenk]

We planted 2 June last year and they both looked good up till about a week ago. Then, the one side of one plant started to die. We left for a few days vacation on Sunday about about half the plant looked bad...it's worse now. This is a rather dry bank under some old pine trees so I watered it fairly heavily and then, we had a fairly wet spell...it's been drying out but then a few day later, we get .5" of rain. The mulch around it always looks damp and I'm wondering if it's just too much water. Or, perhaps it's just getting toward the end of summer. The other June that was planted at the same time looks find as does the one I got from Chris this spring.

The little pair of leaves in the middle look like Chestnut...probably planted by a squirrel.

Host June with possible crown rot

DSC_20120816_125118 by jerryshenk, on Flickr

Closeup of the bad plant

DSC_20120816_125144 by jerryshenk, on Flickr

The good plant

DSC_20120816_125110 by jerryshenk, on Flickr

The entire grouping - sick June in the lower right, good june just to the left of center on the bottom

DSC_20120816_125100 by jerryshenk, on Flickr

[HostaDesigner]

This looks like Southern Blight. Not crown rot. The close-up pic shows what appears to be the small white/orange "seeds" at the base of the scape. Crown rot is the crown of the plant actually rotting and turning to mush below the soil surface. SB is the petioles rotting at the surface of the soil due the the SB fungus in the soil. By the pics, it looks like the mulch was too thick and buried the petioles too.

[Mark Raw]

In my experience with June it shouldnt be sjowing signs of autumn die back yet as it is among the longest lasting hostas well into November here. I would not sat crown rot either as that (as stated above) is more centre rotting. To be honest I would be tempted to dig that one up washe the roots and replant less deepy in a less wet area. I know there are several versions of June some (like mine) are the more subtley coloured others are more Yellow and brighter centred as yours looks to be. Even is direst sun mince never gets the full yellow centre.

[jerryshenk]

So, I guess the solution is 10% bleach-water and soak the entire affected area well?

http://www.americanhostasociety.org/SouthernBlight.html

...or dig it up, clean it and re-plant it...maybe both.

[HostaDesigner]

I've fiddled with the bleach in the past with decent results but not 100%. I just went ahead and bought the fungicide Prostar and treated with multple soil drenches. It completely cured the SB in the gardens. No signs for years now. There are other fungicides that work too, but Prostar was my choice. I ordered in from my local farm supply store.

[Chris_W]

There is absolutely no need to dig the entire plant. Southern Blight is a fungus that only attacks the petioles and will only live in the mulch and no more than the top inch of soil, so you never have to dig the entire plant.

I don't have a lot of time to finish writing now but I just wanted to save you the headache of trying to dig the plant and/or trying to kill it with a bleach bath. I'll be back to help more later.

Chris

[jerryshenk]

OK, great! Less work is always better;)

I did look at it a little more and scrape some mulch back (not spread all over though) and when I did, the remaining leaves all fell out. I threw 'em in the trash can.

[Chris_W]

Sorry I was too busy to reply earlier. Like hostadesigner mentioned, this isn't really crown rot as Southern Blight is only on the surface and really only rots the petioles. The hosta crown itself is not really affected and the roots are never affected so it is never necessary to remove the entire plant. Unfortunately that instruction has become gospel on the internet, but it really isn't true.

When you have a plant with Southern Blight you want to catch it as soon as you see it. The most important thing is to try and get all of the fungus containing mulch and soil away from the crown and scoop up all of the mustard seeds (sclerotia) and cottony webbing (mycelium) and throw it in the trash. I just get a plastic trash bag and disposable gloves, gather up all of the stems that are rotted, scoop up all of the mulch from around the plant that might be harboring the fungus, then scoop up the top layer of soil from around that particular plant (scoop up as much dirt from around the crown as you can, down a couple inches if possible) and get it all in that trash bag. You do NOT want the sclerotia (mustard seeds) spreading around the garden, so getting it out as fast as possible really helps.

The next step is to treat the crown and surrounding area with a fungicide that is specifically indicated for Southern Blight. The best ones contain flutolanil, fluazinam, and when used at a high rate tebuconazole. The last one is often found at stores that sell chemicals to home gardeners, such as in Bayer Disease Control, but may not be the most effective. The others are pretty expensive but if you have a big problem the cost could be worth it.

Some people swear by a bleach drench, and say to take 10% bleach, drench the crown and soil, then rinse away so as not to damage the plant any further with the bleach. This method actually might work but only because the soil is being rinsed away from the old crown and that's where the fungus lives.

After drenching with a fungicide you should topdress with fresh soil and fresh mulch, but keep the mulch away from the crown as it might hold too much moisture and trigger the problem again later.

Soaking the entire plant in bleach may do more damage than the fungus itself would have done, and even if it didn't damage the plant may not do anything to stop Southern Blight from returning since it is a soil borne fungus and not actually in the plant itself. That's another reason why lifting the whole plant is not necessary.

Some varieties of plants do sometimes completely succumb to Southern Blight. I've seen patches die out in other perennials like Ajuga and Lamiastrum and in those cases it may be best to dig and discard the affected plants to make sure you get as much of the fungus as possible.

Finally I would recommend following up with another fungicide drench as a preventative, at least again early next summer before the heat sets in. Then remember that Southern Blight is activated by heat and moisture, so allow the soil surface to dry out when temps are up into the 90s.

Hope that helps!

Chris

[viktoria]

I have only seen this half a dozen times in my garden (15 years, thousands of plants). Each time the bleach treatment has worked and the hosta has returned in good health. Nearby plants have never been affected and the few occurrences have been years apart and in distinctly separate parts of the (large) garden.

Viktoria

[Chris_W]

Hi Viktoria,

When you say "the bleach treatment", what did you do? Did you clean up all the gunk and then pour bleach over the plant? Just wondering what your protocol is for this.

And to clarify, even if you do nothing the plant should almost always come back. Years ago I had a few plants in my gardens that would get this, before I was a hosta grower and knew what it was, and all I did was clean up the gunk and let it dry out. Every hosta always came back, and while I rarely saw the same plant get it again, the fungus would show up in another spot the next year. After I started selling and found out what this was, I used the Bayer Disease Control product with (at double strength) and drenched the whole garden twice in one summer and never saw it anywhere again.

I just cringe when I hear about people lifting whole clumps, soaking in bleach, and then saying that the plant didn't come back and "succumbed to the rot". I've never had a case where a hosta had southern blight and did not return. It sounds to me that the hosta succumbed to soaking too long and/or in too much bleach.

[viktoria]

Hi Viktoria,

When you say "the bleach treatment", what did you do? Did you clean up all the gunk and then pour bleach over the plant? Just wondering what your protocol is for this.

I prepared a quantity, depending on the size of the plant, of 10% bleach solution (1 part bleach, 9 parts water), removed all affected leaves but nothing else, and used a sprinkler can to drench the estimated area of root spread plus the crown of the plant. Putting the leaves in the trash instead of the compost is the best idea but, since my compost is a "landfill" area and I do not use material from there in the garden, I suspect that is where the leaves went each time. 2-10 minutes later I used the hose to thoroughly wet the area to dilute the bleach.

My method may not stand up to scientific scrutiny but it worked for me!

Viktoria

[Mark Raw]

I've never had southern blight. In fact until now I never even heard of it.

[boops]

I have lost 2 Heuchera to something or other-the leaves just up and died. I'm thinking too much moisture and not enough sun to dry up everything. Up here we went from drought conditions to constant damp, wet weather and a lot of torrential rains.
I don't think your supposed to mulch close to the stems, foliage, leaves etc. I always draw a circle a few inches from the plants "trunk"(any plant) and mulch out from there. Even trees aren't supposed to have mulch up to the trunk. I don't add much mulch to my Hosta areas, Only for decorative purposes.
see this link:
http://pss.uvm.edu/ppp/articles/propmulch.html

[jerryshenk]

We've been on vacation this week..mostly out of the area including college drop-offs. I think I'll try to find some of that Bayer Disease Control. Now that I'm digging into this, I recall seeing some mulch that had this "white stuff" this spring. It may not have been Southern Blight but I'm a bit suspicious. No way to tell at this point.

The mulch ended up a piled up on a few plants because of the slope...at least that makes it easier to have that problem. This particular hosta had at least 2" up the stems. I need to be a little more careful to keep the mulch back a bit and pull it back if it starts sliding down the bank too much. This bank was also a pretty dry bank with little organic material so I won't need to put much down in the future.

Thanks for all the advice.

[thy]

Chris.. when you say mustard seeds I expect it to be something else than real mustard seeds.... something looking like mustard seeds... Is it correct ?
Have a lot of mustards as ground cover in the back garden


Mark, that's interesting... the h. June story Years back there were a lot of tak´lks about differnt sorts of June - an euuropean and a US ones more or less. I had 2 h. Junes, very different as juvenile, so I bought two more to compare, they all looked different but it was a question of the amount of sun they got. 2 of them were planted with just one foot in between, and, .. they were different, soft yellow to a bright yellow and in full sun mine got a close to white center , but in the shade they got a bluish center sort of mixed blue and soft yellow... not acting like paint and becoming green, but a softer sort of blue opposite to the real blue margin.

Please can you do a pic and start a new tread, think a lot of us want to know if there really is a special June
Paradise Joyce is nore blue, but I think you are sure it is a h. June

[jerryshenk]

Is this what I'm looking for:
http://www.lowes.com/pd_100375-24182-70 ... facetInfo=

It doesn't specifically mention either hostas or Southern Blight but, it does mention fungal diseases.

BTW, I just found more damage on two other hosta plants. Those have some unaffected leaves but, given a little time, it will probably take all those leaves out too.

[Chris_W]

Unless they changed the chemical for this then yes, that's the product. Don't use the "3 in 1" because the fungicide is diluted way too much to be effective on Southern Blight. Check the label and make sure it is still tebuconazole.

[jerryshenk]

yes, still tebuconazole - 2.90%. I got it and applied it the the entire area. I'll keep an eye on things...hopefullly we'll see some new growth.

[Mark Raw]

Re the June colouring. My June is an old one and has been divided several times, it stays the same subtle darker colouring no matter where it is places (shade or sun) it's divisions do the same. Most of the junes I have seen for sale recently seem to be the more yellow/brighter centered ones. I have never really known if they are true Junes or its sports or perhaps tissue clones. To be honest I have not seen a darker coloured June in a long time, always used to think it was because they were grown in bright sun but it appears not. I do find at quite a few garden centres there are many wrongly labeled hostas and some are quite obvious such as the liberty that I bought (full well knowing it was a Queen Josephine) as it was very cheaply priced. Still doesn't explain why the Patriot I bought was a Cordelia that this year looks like a small Barbra Ann-now dark green centred with a narrow white marin. Bit I digressed a bit there off the June subject. as you do ahem.

[thy]

Mark, what's on your wishlist ????

Can we do a trade ?

Mark Southern blight is NOT usual in Northern Europe. I have heard about it one time.. from a green house and seen it once.. in my D.D.'s garden, a very small city lot with highh walls on 3 ½ side

Pia