Slime mold can occur on all turf grasses. The disease does not infect the plant but instead grows on the outside of the leaves. Yellowish, purplish, or grayish fruiting bodies may be observed during wet periods. As the turf begins to dry, the structures become powdery. Since the disease is only cosmetic in nature, chemical control is not recommended. To remove the unsightly fruiting bodies, consider mowing, raking, brushing, or hosing off with water.
For more information about slime mold, please visit: http://www.extension.purdue.edu/extmedia/BP/BP-112-W.pdf