Hosts
Slime moulds (Myxomycetes) occur widely, living among decomposing plant material. Some are prominent on lawns, where they live among dead grass. Others live on dead wood and fallen leaves and in soil.
Symptoms
The slime moulds which appear on lawns are not pathogens. The structures that appear suddenly on lawns are aggregations of individual slime mould cells called sporangia. The ones appearing on lawns are often grey or brown, but others can be brightly coloured. The organism causing club root of brassicas is a different type of slime mould, which produces no structures visible to the naked eye.
Biology
The individual cells of slime moulds are microscopic and amoeba like. They are probably more closely related to protozoa than fungi. They feed mostly on bacteria. At certain times, probably when the food source is exhausted, they aggregate to form the visible sporangia, which then liberate spores. These structures are formed very rapidly, sometimes overnight, but disintegrate as soon as the spores are shed.
Control
None necessary, slime moulds are beneficial in helping to break down decaying plant remains.