Southern Blight?

[jerryshenk]

Does this look like Southern Blight? Notice the "snow" under the hosta?

DSC_20130628_070106 by jerryshenk, on Flickr

Here's a closer shot:

DSC_20130628_070128 by jerryshenk, on Flickr

And even closer:

DSC_20130628_070224 by jerryshenk, on Flickr

It's been pretty warm for awhile and this week has been muggy, high humidity, intermittent rain, the other night we got about an inch. This "snow" is all over...just about everywhere there is mulch. The hosta garden is by far the worst but, I suppose I need to try to eradicate this. I first noticed this late last summer and used the "Bayer Advanced Disease Control" on it. Is that my best option to combat this?

[jerryshenk]

I've done some research and here are a few links - partly for my lookup, partly to share;)
http://www.apsnet.org/edcenter/intropp/ ... light.aspx - rather scary, thorough, scientific description
http://www.extension.umn.edu/yardandgar ... light.html - also scary and scientific
http://www.aces.edu/pubs/docs/A/ANR-1157/ANR-1157.pdf - this stuff seems pretty bad - eradication thoughts
http://forums.gardenweb.com/forums/load ... 26716.html - post about halfway through introduces Bayer Prostar 70WP and Scott Contrast 70 WSP - they are the same thing, very hard to find, expensive but cheaper than a whole hosta garden;) and it sounds like it works. the 70 in the name stands for 70% and the fungicide is flutolanil.
http://forums.gardenweb.com/forums/load ... 32360.html - another thread on the subject, references an AHS article that talks about using Bayer Advanced - different chemical, more easily obtained. This fungicide is Tebuconazole.
I found a number of links to Prostar 70 WD (same thing but a powder) in 3 lb. boxes for $215 - I believe 1 oz makes 30-50 gal of soak - 3 lb would last a LONG time
Still looking for reasonable quantities of this stuff. I may start with the Bayer Advanced.

[Chris_W]

No, that isn't Southern Blight, but just some kind of fungus that seems to only be growing on the decaying mulch. I kind of doubt that it would hurt the plants, but I'll look into it a little for you. Personally I'd just hold off on the watering and try to let the mulch dry out rather than worry about a fungicide spray. And while I don't recommend using bleach directly on plants, in this case a bleach spray to the mulch might help to clean up the white mold from the garden.

Unless you actually see a problem with the plants I wouldn't worry about this.

Chris

[jerryshenk]

I had something similar last year that I ended up calling Southern Blight (correctly or not). I did spray things pretty heavily with Bayer Advanced this morning...wanted to knock this down before it messed up the garden like it did last year.

Here are two pictures from last year. This particular plant came back, slightly smaller with very little sign of [whatever] this morning. This was not the only instance of the fungus from last year but it was the worst.

DSC_20120816_125118 by jerryshenk, on Flickr


DSC_20120816_125144 by jerryshenk, on Flickr

[Chris_W]

Yes, your last pictures ARE southern blight, so spraying again for that this year would be recommended just as a preventative then. But the white fungus on the mulch is something else.

Southern blight will develop with a combination of high temperatures and high moisture/water levels. To help prevent it you should not water during hot (90+) weather and allow the surface to dry out between waterings. You might also want to pull some of the mulch away from the stems.

Good luck and hopefully the southern blight from last year won't come back.

[jerryshenk]

Oh, so this is two separate issues? Now that complicates things;) Well in that case, I just did a preventative application of Bayer Advanced to avoid a recurrence of the Southern Blight.

This week, the watering is pretty much out of my hands...it's not gonna dry out much till the middle of next week.