Slime molds have recently been spotted by home gardeners on turfgrass and the lower leaves of tomato plants. Slime molds are colorful organisms that usually appear in warm, muggy weather after a rain. They first develop as a yellow or orange slimy mass and can ooze over areas a foot or more in diameter. As the weather becomes dry, most slime molds develop into crusty structures that are typically filled with dark spores.
Slime molds are usually found on mulch, turfgrass, and other low-lying vegetation such as strawberry leaves or the lower leaves of other garden plants. They do not infect plants, but simply use them as a surface to grow and reproduce. They feed on dead organic matter and on bacteria and fungi found in the soil.
Slime molds are more of a curiosity than a problem. They will disappear if left to complete their life cycle. If their appearance is bothersome, they can be broken up with a rake or a strong stream of water.