Let’s start with the pest. The Fairy Ring mushroom (Marasmius oreades) is the one species that most lawn aficionados hate. Usually, this fungus first noticed as a ring of mushrooms with dead or dehydrated grass occupying the middle of the ring. The reason the grass dies is due to the high density of waxy mushroom ‘roots’ (properly called hyphae) that shed water away from grass roots and compete for space.
There are no registered chemical controls for Fairy Ring fungi, but the “poke and soak” method can be used to, at least, reduce the severity of the fairy ring.
“Poke and soak” involves using a root feeder (hollow metal stake with reservoir on the top), hooking a garden hose to it, and then stabbing it into the ring and turning on the water. Water that penetrates into the ring not only helps to hydrate the grass roots but it always encourages the growth of microorganisms that compete with the Fairy Ring fungi. Adding some horticultural soap to the reservoir will make the water “wetter,” and allow better water penetration around the hyphal strands.
The “poke and soak” method is not perfect, but it helps.
Non Fairy Ring mushrooms that emerge after thunderstorms are just the fruiting bodies of fungi that are consuming organic matter in the soil, including bark, compost, dead roots, and more. They are not plant diseases, but instead, are saprophyte which means they are fungi that eat non-living organic matter. Saprophytes are, actually, beneficial for soils in lawns and gardens. Rather than trying to kill these mushrooms, I say, grow to love them…if you can!
Now if you are thinking that you would like to add some of these lawn mushrooms to your pizza, don’t do it unless you can - with absolute certainty - correctly identify which ones are edible and which ones might be poisonous.
There is a great aphorism that I love about mushrooms. It goes like this: "There are old mushroom pickers and there are bold mushroom pickers, but there are no old, bold mushroom pickers!”
- Jim Hole