Rhizoctonia species are strong saprophytes. They are able to survive for extended periods of time in the absence of living host plants by feeding on decaying organic matter. When conditions are not favorable for growth, these fungi persist as mycelium or as sclerotia in the thatch and soil. When a host plant is present and environmental conditions are favorable, Rhizoctonia species begin to colonize the surface of the potential host plant with long, unbranched hyphae called runner hyphae (Figure 27). Depending on the isolate and host species, the runner hyphae may branch and penetrate through stomata or give rise to structures called infection cushions, which are aggregates of convoluted hyphae (Figure 28). Infection cushions of R. solani form most frequently along the edges of the vascular bundles (Figure 29) or over stomata. The infection cushions are involved in enzymatic degradation and physical penetration of the leaf surface, providing entrance into the plant for the pathogen. When sufficient moisture is present, Rhizoctonia species spread from plant to plant through the growth of hyphae among plant leaves