A mushroom sprouts from a Maine lawn in September 2021. Credit: BDN file photo

Story by Seanna Annis, Associate Professor of Mycology and Associate Extension Professor at the University of Maine.

With the rain we have been getting this fall, we are seeing fungi popping up in peoples’ yards, fields and woods all over the state. 

These fungi typically have been present for years, growing underground until they have sufficient nutrients and water to produce their fruiting body or mushroom where we can see it. The fruiting body is equivalent to a fruit on a plant and helps the fungus disperse itself through spores.

Most fruiting bodies last less than a week since they release spores that are dispersed by wind for a few days, and then rot from other fungi or bacteria eating them. 

The fungus under the surface of the ground consists of fine strands called hyphae that support the production of the fruiting bodies and form a much larger and longer living structure than the fruiting body — and it can persist for years or decades. 

Most of these fungi are providing valuable services to the plants near them. Many are breaking down dead plant material and returning valuable nutrients, such as nitrogen and phosphorus, to the soil for plants to use. 

Some fungi have a more direct role in interacting with plants and are in a mutually beneficial symbiosis with plant roots, particularly shrubs and trees, called mycorrhizae.  Mycorrhizal roots have fungus growing around or in the plant roots in close contact with plant cells and the hyphae of the fungus extended out into the soil around the plant. The fungus collects nitrogen, phosphorus, other nutrients and water and gives it to the plant through the mycorrhizal roots. The plant, in turn, gives plant sugars to the fungus to grow.

It is estimated that 90 percent of plant families have mycorrhizal roots. Many mycorrhizal fungi also protect the plant against harmful fungi that cause root rot or against other organisms, such as bacteria and plant pathogenic nematodes (microscopic worms), and improve soil quality.  

Without mycorrhizal fungi, many plants do not thrive and many cannot grow in the forests, bogs and other ecosystems in Maine.  

Many landowners ask how to get rid of the fruiting bodies on their lawn.  

Unfortunately, there is no way of doing this without removing all of your plants. Spraying fungicides on the lawn will not penetrate down to where these fungi are growing and may damage beneficial fungi and plant roots. Fungi are inhabitants of all soil types and usually are interacting in a beneficial way with nearby plants.  

The fruiting bodies should only be around for about a week or two of the year and can be safely removed and thrown in the compost or garbage.  

Do not eat any fungus unless you have confirmed with a mushroom expert that it is edible. If you eat most of the fruiting bodies growing on lawns, they will give you diarrhea and vomiting that can be severe. Eating the fruiting bodies of some fungi can cause severe poisoning with damage to the major organs, particularly the liver and kidneys, and can result in death.