Plant Pathology Infobytes

June 28, 1996
Slime Molds - No Danger To Your Plants

County Extension Offices over the state have received calls about brown to pinkish layers of growth which are currently showing up in home landscapes. This growth is actually a harmless type of fungus known as a slime mold. Slime molds come in a variety of shapes and colors, but none are known to cause plant health problems.

Slime molds never fail to attract the attention of gardeners and home landscapers who are convinced these creatures are ready to attack landscape plants and turf grass. Although slime molds have an alarming appearance, they grow externally on the surfaces of leaves and stems without parasitizing plants.

Slime molds normally live on or close to the soil surface where they feed on decaying organic matter. They move about in a manner more closely akin to animal than plant life, creeping along by forming finger-like projections. These projections pull the body of the slime mold across the soil surface.

When the slime mold is ready to reproduce, at some point during spring or summer generally following a period of rainy weather, it "crawls" up on grass blades, lower stems and foliage of landscape plants, the surface of landscape mulch, or even garden hoses. From these locations, the slime mold releases millions of dusty-gray

spores. Spores are tiny "seeds" which will insure future genera- tions of slime molds. Its only purpose for selecting locations above the soil line is to insure distribution of spores over afurther distance than it would be possible from the soil surface.

Since slime molds don't feed on living plants, control measures aren't necessary. However, if they become too numerous and unsightly, break up the spore masses by raking, brushing, or hosing down with water. Fungicide sprays as a means of slime mold control are not recommended.

If you need further information, please feel free to give us a callat the County Extension Office.


Written by the late Dr. Frank Killebrew

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