Robyn Stewart
Seemingly overnight, homeowners may find a gross-looking substance in their gardens and lawns. The past few weeks of hot, wet weather have caused the presence of mushrooms, molds, and other fungi to be prominent. I had a client bring a sample of slime mold to me this week and wanted some more information on it- so here we go!
Slime mold is actually not a fungus, but it is a type of amoeba that moves around to find sustenance. They belong to a group of organisms called myxomycetes and can be found all over the world. Actual mushrooms and fungi are stationary and release enzymes to break down and absorb their food. Slime molds go through several stages of development. They begin in a cellular stage with a single cell on a substrate like mulch, bark, or leaves. Eventually, the single cell finds other cells and fuses with them to form a plasmodium. As the environment gets hotter and drier, the plasmodium transforms into a dark colored cushion called an aethalia. The stage of slime mold you’ll most commonly see in your garden or yard is the plasmodium feeding stage. While slime mold doesn’t have a brain, it is capable of moving around to find food in the form of bacterial and fungal spores. The organism can move several feet per day in the right conditions. The mold can range in size from several inches to several feet in diameter, and can be a variety of colors.
Slime molds live in areas with moisture and decaying organic matter, like the mulch of your garden or pine straw under some trees. They are really only viable in wet conditions—as soon as the environment dries out and growing conditions are no longer favorable, the plasmodium will shrink and produce spores for reproduction (the aethalia stage). The spores are moved via the wind and animals to colonize new areas during the next wet spell.
The appearance of a slime mold overnight can be concerning for many homeowners, but fortunately, they are pretty harmless. While slime molds may grow on plants, they do not feed on them, so the plants are largely unaffected. The biggest concern with the presence of mold on plants is if the plant cannot receive enough light to conduct photosynthesis. Control with the use of fungicide or other methods is typically not necessary as the slime mold will disappear as soon as the area dries out. The physical removal of the mold by raking, scooping, or washing it out of the area with a hose are all options if you feel the need to do so.
The Lincoln County Extension Office is happy to offer identification services, from slime mold, insects, weeds, plant diseases, and more. If you need a free consultation, please reach out to us at uge3181@uga.edu or 706-359-3233. Remember we have moved to our new office at 2080 Rowland-York Drive!
