Controlling Lawn Insects Bluegrass Billbug Adult billbugs are dull gray to black or brown beetles with a snout or bill. The wings are scaly textured but the insects seldom fly. The larvae are white, humpbacked grubs with a yellow to brown head.
Symptoms are irregular patches of dead grass, especially near sidewalks or curbs.
The dead grass pulls out easily and has hollow stems. The larvae are present under the grass and brown sawdust-like frass is present in the root zone. The adults can be found in the grass near the dead areas. Apply controls for adults in late April or early May before egg laying begins. Larval controls should be applied in mid to late June or July when early injury may be apparent.