Often during the late months of summer we receive calls from customers who are seeing mushrooms in their lawn. This usually occurs during periods of summer when we are seeing extremely high levels of rainfall on a daily basis along with higher levels of humidity. Generally the mushrooms are never a problem however some mushrooms are associated with a problem known as fairy rings. Fairy rings can occur in all warm-season turf grasses in Florida whether it is St. Augustine, Bahia, Zoysia, etc.
The cause for this problem is when large quantities of organic matter such as old wood from tree stumps, tree roots, or lumber that have been buried deep within the lawn. When conditions are appropriate such as the heavy rainfall from summer this fungus can develop from this buried material. The mushrooms in a sense are the fruit that comes from the mature stages of this fungus.
Fairy ring comes in three different types. Type I is indicated by a dark arc of green grass often with dead grass within the arc or circle. Generally weeds will invade the area of dead grass as a result. Type II will generally be just a dark arc of green grass either with mushrooms present or without. Type III will not present a dark arc of green grass or a dead zone but will have a row of mushrooms in a similar arc or ring like shape. The picture above is an example of Type II fairy ring.
The mushrooms are generally poisonous so it would would be wise to remove them or chop them up with a mower if you are seeing them in your lawn. Often lawns that experience this fungus will see it in the same areas every year since it is coming from a direct source of organic matter beneath the turf. Fungicides can be used if necessary to inhibit the fungus however they will not do anything for the dark green circles or any dead areas.
As mentioned before if you are seeing mushrooms in your lawn during the rainy part of summer they are generally nothing to worry about. If you are seeing a dark green arc or circle like pattern in your lawn or areas that are dying then you may have fairy ring fungus and may need a fungicide treatment. Give us a call if you are seeing any of the above symptoms in your lawn.