What do green pellets (frass) indicate in relation to sod webworms?

Green pellets, known as frass, are a byproduct of sod webworm feeding activity. The presence of these pellets on the turf indicates that the sod webworms are actively consuming the grass blades. Turfgrass managers and lawn owners can use the observation of frass as a diagnostic tool to understand the level of infestation and the corresponding need for management practices.

While other options might relate to turf health, they do not specifically connect to the frass produced by sod webworms. Grubs typically produce different types of waste, signs of root damage would be indicated by other symptoms in the turf, and increased insect populations might be inferred from frass but are not explicitly denoted by its presence alone. Thus, the frass is a direct indication of the feeding activity of sod webworms.