Billbugs
Weevil-like beetles whose larvae feed inside grass stems at soil level. Billbug damage appears as brown, dying patches in summer that tug out of the ground easily because the roots are severed. Zoysia and Kentucky Bluegrass are especially susceptible.
Billbugs (Sphenophorus spp.) overwinter as adults in the soil and lay eggs in early summer. The larvae (white grubs) feed on the grass stem just below the soil surface, severing the root-to-blade connection. This differs from white grubs, which feed on roots deeper in the soil.
Diagnosis: Grab a handful of brown grass and tug. If the blades pull out easily at soil level with no roots attached, billbugs are likely the cause. Look for sawdust-like material at the base of stems.
Control: Preventative applications of imidacloprid or chlorantraniliprole in late spring catch eggs and young larvae before damage occurs. Curative treatments in summer are less effective.
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