Bluegrass Sod Webworm

An adult Bluegrass Sod Webworm can be identified by its white head and snout that are both gray to light brown on the undersides. The forewings of this lawn-destroying insect have seven spots along the wing tip, and a curved, brownish-orange line that runs across the wing, just inside the tip—its veins are usually distinctly lighter in color. The larvae of the Bluegrass Sod Webworm have blackish-brown head capsules and translucent, yellowish bodies (which appear green after feeding). Adults are often seen flying out of a lawn when disturbed. Bluegrass Sod Webworm lawn damage initially begins as thinning of the grass, followed by small brown patches appearing in the lawn. As this lawn pest's larvae develop, these brown spots can grow to several inches in diameter. A close examination of your yard will reveal short green stubs of grass left behind by the grazing larvae. Silk-lined tunnels in the thatch or upper soil may also be found. Severe Bluegrass Sod Webworm infestations can result in large, irregular patterns of sparse turf. The damage is comparable to scalping your lawn—or mowing it too low—and the effects are somewhat similar. Damage from this lawn insect is often found on south-facing slopes. Well-maintained grass can mostly tolerate this damage, but stressed yards may begin to show signs of dying off as crowns are exposed to sunlight.