So, what is the final, ultimate solution to my problem?
Take out all of the infested mulch (usually just around the foundation - not out in the yard), bag it in a biodegradable bag, and take it to a landfill. Then put down a layer of black plastic, and overlay it with stone or an artificial (non-organic) mulch.
But, I don't like stone - it's so cold!
I want to stay organic, and, like, use, like some sort of wood/bark mulch. Yet I can't stand the artillery fungus. It's driving me bonkers. What should I do?? I'm at my wit's end.
Well, then, you have to learn to live with the problem. That is, you cannot beat the artillery fungus (at this time), so manage it. Use mulches that the artillery fungus doesn't like, such as large pine bark nuggets. Then, put down a fresh layer of mulch each year - we have no evidence for this, but yearly applications of layers of mulch really seem to inhibit the artillery fungus.
Another possibility, but one we haven not investigated, is to use ground cover such as ivy, periwinkle, or pachysandra in place of the mulch around your foundation. It seems likely that the artillery fungus would not grow well under the canopy (on the fallen dead leaves) of such ground-cover plants. Or, establish lawn right up to your foundation. An artificial mulch made of plastic, old tires, etc. should work, but we have not tested it.
Do you ever get suggestions about removal of spores from surfaces like cars or houses, and have you tried any of them?
Yes, I have received many suggestions regarding removal of spores from cars or houses. I have not tried any of them. I have listed a few suggestions from readers below, but I emphasize that these have not been tested are not my recommendations.
Note that most involve abrasives, and a lot of "elbow grease", especially if the spots have been on the surface for some time! So, one is really just scraping off the spots, which may land back in the mulch... Having said that, please let me know if any of these actually do work! Again, these are not my recommendations.
OK, I am going to remove my old, infested mulch. But, what do I do with it?
The best thing to do is probably bag it in a biodegradable bag and take it to a landfill. At least the mulch is organic and will rot away. Make sure you don't put the infested mulch somewhere where you could be held responsible for someone else's artillery fungus problem. This is out of my field, but it has been suggested that the infested mulch could be put in a yard waste-composting facility. But you really need to ask this question to a "compost expert."
Will used "mushroom compost" suppress the artillery fungus?
Used mushroom compost, also known as "mushroom soil," "spent mushroom substrate (SMS)," and even "black gold" is a great product, if you live in an area where you can get it! Mushroom compost has many beneficial aspects for gardeners, one which is that it supports micro-organisms that inhibit many unwanted pest fungi. Mushroom compost is pasteurized before it is used to grow mushrooms, and then the used compost is pasteurized again when it leaves the mushroom house, so it should not contain weed seeds. Our research at Penn State has shown that blending used mushroom compost with a landscape mulch at about 40 % will greatly suppress artillery fungus sporulation. Mushroom compost is very "green" and environmentally friendly.
Are there any registered fungicides that will kill the fungus?
There are no fungicides labeled for use against the artillery fungus in landscape mulch. Bleach, if it worked, would be very temporary, since it leaches out with each rain. We have tested many different fungicides in the laboratory, but have to take the experiment to the field.