The term ‘Sod Webworm’ refers to a variety of species of nocturnal, grass infesting moths and their larvae. The larvae line their tunnels with a silky, web-like material.
Upon hatching, most larvae burrow into the thatch and conceal themselves with debris. They remain concealed during the day, and wander out at night to feed. They damage turf by chewing at the crown of the grass plant or by cutting blades and bringing them into their tunnels for food.
By late summer or early fall, the young adult moths emerge and fly just above the turf, being especially active at twilight. As they are nocturnal feeders, applications should be made as late in the day as possible.
• Small brown patches of turfgrass with ragged appearance.
• Chewing damage on grass blades.
• Green excrement (frass) on the surface.
• Silken tunnels in thatch.