Slight damage may occur when leaves are smothered or shaded for several days to a week. The weakened and somewhat yellow grass leaves are more susceptible to killing by secondary fungi and bacteria. An abundance of straw mulch favors slime molds by providing a ready source of organic matter and high populations of microorganisms. No control measures are usually considered necessary. If the molds are abundant, the unsightly spore masses may be broken by vigorously raking, brushing, poling, or hosing down with a stream of water.
Washing is suggested only after the onset of dry weather.
Mowing the grass usually removes the spore masses. Although many fungicides might be beneficial, they are not recommended. For further information concerning turfgrass diseases, consult an Extension Specialist, Department of Crop Sciences, University of Illinois, Urbana. University of Illinois Extension provides equal opportunities in programs and employment.