Slime molds often grow across the surface of fresh mulch in the garden. These organisms feed on bacteria and yeasts in the soil and on the mulch. During cloudy, humid weather these molds grow on the mulch and sometimes on nearby plants. These fungi do not feed on plant tissue. Some damage may occur, however, when the fungal growth is heavy, causing the shaded plant parts to turn yellow. Although the "dog vomit fungus" is the most common of the nuisance fungi growing on mulch, other nuisance fungi such as stinkhorns and the artillery fungus also populate fresh mulch.
Controls are generally not necessary since slime molds do little harm and usually disappear with the onset of dry weather. Mulch that has been composted before application is less likely to support growth of nuisance fungi such as slime molds. When slime mold infestations are heavy, spore masses may be broken up with a rake or a broom. Applying a strong stream of water is also effective but should only be done after the onset of dry weather when the threat of further development is past.
