Cup fungi are very interesting mushrooms with an inverted cap that is cup shaped instead of domed. The fungi do not have a stalk but instead attach themselves directly at the base of the cup. They may be found fruiting on the ground, on logs or around other organic-rich surfaces. The inside of the cup bears the spores that are a fungus’s method of reproduction. Cup fungi span numerous genera and may be microscopic or as big as nearly 2 inches across. As with most fungi, cup fungi require consistent moisture to grow and fruit. Often killing the organisms just requires drying an area out. Fungicides or manual removal are also effective.
Check for leaks in the area where you are experiencing cup fungi. Check hoses, drainage paths and runoff areas for excess moisture and fix any plumbing or loose connections that may contribute to moisture buildup.
Remove the mushrooms with a shovel. Scrape off the top 1/4 inch of soil and discard the mushrooms and soil. This will remove the mycelium that grows from the base of the cups and attaches the fungus to the soil.
Apply a fungicide powder at the rate the package indicates for the area infested. Work the fungal powder into the area where the mushrooms were growing.
Reapply the fungicide after periods of excess moisture. Small amounts of the mycelium may still be in the soil and can bloom again when temperatures are warm to mild and rain or irrigation triggers the mycelium to fruit.