A month and a half ago I planted a number of horsetail reeds in a bed in my back yard. I noticed that one of them had a small, nondescript fungal growth on some of its roots that had become exposed, so I sprayed it down with a slurry of liquid copper and sulfur in water, assumed that would do the trick, and forgot about it.
Two weeks ago, I had a layer of mulch put down across my entire yard.
Four days ago I discovered this crazy shit:
That is one of the smaller patches. There are at least 30-40 individual patches that I have spotted so far and I'm finding more every day. They are appearing in both my front and my back yard. Some of them are growing on dead plants, some on live plants, most of them in the middle of open soil/mulch in all levels of light.
As for the fungus itself, it's one of the weirder ones I have ever seen. In the photo you can see what I assume is the fruiting body--irregular mound-shapes covered with a thin layer of crusty white stuff. Below that is a thick layer of powdery, dark brown spores that is between 1 and 2 cm deep. When the mounds are disturbed violently enough to penetrate the crusty outer layer, they fling out huge clouds of spores. Below the spores there is bright yellow spongy flesh. And the weirdest part is the rhizomes (I think that's the correct term for fungus?). They spread out from under the mounds and look for all the world like god damn cobwebs. As far as I can tell this stuff is all on the surface and the rhizomes tend to be fully exposed until a spore-mound grows over the top of them.
My main concern here is that my sister has asthma and I'm concerned she might inadvertently kick one of these things, inhale some of the spores, and have an attack. To a lesser extent I'm also kind of worried this is going to start killing my plants. I have tried (repeatedly) to kill this stuff with the same liquid copper and sulfur solution I mentioned earlier, from a pressure sprayer, with no visible effect other than disturbing huge clouds of the spores to the point that I'm afraid to try it any more without a respirator.
My question is, can anyone identify this and/or recommend a method that I can apply to the majority of my yard that will kill this stuff?
Edit: Forgot to mention that the original growth on the horsetail roots has grown into a patch of this despite early treatment with fungicide, although I'm not sure if that is the source of the entire infestation.