Growth of living organisms results in an increase in the quantity of live tissue. The primary mechanism for this accumulation is photosynthesis by green plants. Harvesting sunlight ultimately provides energy and nutrients for all life.
Decay is as important to maintaining the balance of living systems as growth. Without decay, many substances required for growth would accumulate in dead and dying tissue and become unavailable.
Detritus refers to dead particulate organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms and metabolic waste materials. Communities of organisms that colonize and decompose this accumulated organic material constitute the detrital food web. Microorganisms, including fungi, are essential components of these communities.
Home landscapes may become a reservoir of detritus as lawn clippings and mulch accumulate. University of Georgia Extension recommends returning clippings to the lawn, rather than removing them, to encourage recycling of nutrients necessary for turfgrass growth.
Under conducive environmental conditions of warm temperatures and high humidity, the accumulated organic material will support an apparently sudden growth of fungi, often conspicuous as mushrooms. Recent rains have contributed to conditions beneficial to mushroom establishment and growth.
Mushrooms are the fruiting bodies of fungi that live below the soil surface. Mushrooms often emerge when rain follows dry periods. Dry weather stresses the fungi, and when water becomes available, it triggers the reproductive mechanism and mushrooms pop up. Several types of fungi can show up in the landscape.
One of the most distinct fungi is a type of slime mold commonly referred to as dog vomit. This slime mold typically occurs on mulch. Bright yellow or orange growth usually begins as small areas a few inches across but can rapidly grow to several feet in diameter. As it dries it fades to brown and tan.
Slime molds do not harm plants and usually dry up within a few days of forming. One of their more curious characteristics is that they are actually able to move two or three feet a day. If the appearance is offensive, they can be scooped up and added to the compost pile or thrown away.
Another interesting fungus family includes mushrooms known as stinkhorns. Most people smell stinkhorns before they see them. While their smell or appearance may be undesirable, stinkhorns are beneficial to the landscape by breaking down decaying plant material.
Stinkhorns do not harm landscape plants or grasses. If the smell is unbearable, remove the mushroom and place it into a sealable plastic container.
The octopus stinkhorn is one of the most common and most putrid. The name octopus stinkhorn is fitting for this mushroom that looks like an orange octopus popping out of mulch. It emits a very foul odor.
Circles or partial circles of mushrooms, called fairy rings, mark where a colony of fungi is hard at work decaying organic material. Fingers of the fungi extend radially from the colony, and mushrooms grow where the fingers emerge from the soil.
Fairy ring mushrooms are decomposers that grow in soil with high levels of organic matter and in areas where trees were recently removed. Old tree stumps, logs and roots that are buried in the soil begin to decay and are colonized by various mushrooms. Growths of fairy ring fungi begin in the center of a ring (e.g., near a tree stump) and expand outward in a uniform, circular pattern over time. Mushrooms might only be visible during periods of wet weather, particularly in the fall.
Fairy ring mushrooms do not typically cause the death of home lawns. These mushrooms are mainly viewed as a nuisance and will often disappear as weather conditions change. Waiting for them to disappear naturally is usually the best approach. However, they may reappear during the next rainy season or return for many years, depending on how much wood or organic debris is buried in the soil.
If you want to try to manage fairy ring mushrooms, spraying a fungicide is typically not effective. Consider routine core aeration of your lawn, which can improve drainage and reduce thatch buildup that harbor fungi. Fall is an excellent time to aerate tall fescue lawns.
The main reasons to remove mushrooms are to keep children and pets from eating them and to improve a lawn’s appearance. Never eat an unidentified mushroom, as some mushrooms are poisonous to humans and animals. The best way to keep mushrooms out of your landscape is to irrigate before the lawn gets too dry. If it stays somewhat moist, fungi will stay underground and will not produce mushrooms
Roger Gates is the agricultural and natural resources agent for University of Georgia Extension, Whitfield County. Contact him at firstname.lastname@example.org.