Q: Are there any registered fungicides that will kill the fungus?
A: 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.
An article from the Journal of Environmental Horticulture entitled “In vitro screening of fungicides to control artillery fungi” discusses this topic.