Sod Webworms
Sod webworm larvae
Photo courtesy of the University of Nebraska
Sod webworm larvae are cream to dull gray colored caterpillars. They have many pairs of dark spots on their body and are about .75” long at maturity. Sod webworm adults are moths that are gray to tan in color. They have a long snout and hold their wings close to their body when resting.
Damage
Sod webworm larvae chew on grass blades and shoots. This feeding causes browning of turf in irregular patches to form. They also construct silk tunnels in the thatch layer. Green frass pellets are evidence of webworm activity. Probing by birds may indicate the presence of sod webworms. Sod webworms prefer fine fescue and bluegrass in northern areas and do their damage during summer months. Sod webworms are usually not a problem in the south.
Sod webworm adult
Photo courtesy of Oklahoma State University