It's dog vomit fungus (delightful name, no?) and completely harmless.

it actually coming from the soil below ....the hosta just happened to get in the way ...

very common when you have a rotting wood mulch ... or such in the soil ..

ken

This is the voice of experience on fungi. You can have more than one kind at a time and they can and will kill your hosta. Whatever it is, is going to kill that hosta (note the melting petioles at the ground level in photo 2), or at least weaken it severely. The fungus might go away, but it will come back next year if the conditions are right and if not dealt will.

bk

https://store.extension.iastate.edu/ProductList?output=xml_no_dtd&client=default_frontend&proxystylesheet=default_frontend&Keyword=hosta+diseases

I'd ask Chris. http://www.perennialnursery.com/forums/viewforum.php?f=1

Or I'd email him off his site http://www.perennialnursery.com/

I've had SB in my garden several times and that's not what it's looked like here. SB is just so lethal that an infection that severe would have killed the plant already. It's pretty obviously some kind of fungus, I just don't think it's Southern Blight, (Sclerotium Rolfsii).

Copy and paste from the other thread.

Ashley, if Chris can't identify it, I'd treat it with some kind of fungicide. It's hard to say what kind when you don't know which fungus it is. Spraying it with hydrogen peroxide might help.

Depending on how many hosta you have and how important they are to your garden, I suggest you send a sample to your land grant university for a diagnosis. You don't say where you are, but I'm in Texas. Here, we send samples to the plant diagnostic and disease laboratory at Texas A&M. Your state will have something similar. Our cost per sample is $35.00 + you have to overnight ship it. Some states are less expensive. I think someone told me that their state just charged $10.00.

bkay

There is really no question that the substance in the OP's photo is a slime mold, aka dog vomit fungus. And while they appear to be growing on the plants, they are not and their presence is harmless. The "flow stage" (as the pale colored foamy stuff is called) is very temporary, lasting only a couple of days at most before disappearing. The only possible damage they might do is to shade small seedlings. The hostas will be fine........unless there is some other issue going on that is not evidenced in the above photo.

I'm not saying there is not a slime mold there, I have not idea what kind of fungus it is. My question is, if it's a harmless fungus, what's causing the petiole rot? Enlarge her photo and look at it. Those petioles are rotting.

bk

They are rotting. Maybe the slime mold came to take advantage of the rotten plant matter and there is some Southern Blight going on also. It's unfortunate that there can be two things wrong at the same time.

Ashley, can you get a pic from further away so we can see the whole plant? How many of those leaves are flat on the ground?