Grubs (White Grubs)
C-shaped white larvae of beetles — primarily Japanese beetles, masked chafers, and June bugs. Grubs feed on grass roots in summer and fall, causing brown patches that lift up like a carpet because the roots are destroyed. A preventative treatment applied in June–July is far more effective than a curative treatment.
White grubs are the larval stage of several scarab beetles. Japanese beetle grubs are the most common culprit in the eastern US. The adult beetles lay eggs in lawns in early summer; the grubs hatch and begin feeding on roots in late summer.
Signs: Irregular brown patches that appear in mid-to-late summer. Spongy turf that lifts up easily — because the roots are gone. Increased mole, vole, skunk, or bird activity (they dig for grubs).
Diagnosis: Cut and fold back a 1 sq ft section of turf at the edge of a brown area and count grubs. More than 5–10 per sq ft warrants treatment.
Control: Preventative (June–July) with chlorantraniliprole or imidacloprid is far superior to curative treatments. Must be watered in immediately (½ inch irrigation) to move the chemical into the root zone.
More on Bugs & Pests
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