Diagnosing Brown St. Augustine: Chinch Bugs, Fungus, or Both?

Your front yard St. Augustine has turned completely brown. A lawn company diagnosed chinch bugs. You've sprayed insecticide but see only a few green sprigs and moss-like weeds. You're wondering if resodding is necessary or if it will recover in spring.

Critical: Identify the Pattern

• Chinch bugs: Start in hot, dry areas (near concrete). Damage spreads with irregular but advancing edges. Look for bugs at the border of green/brown grass.
• Fungus (brown patch, take-all root rot): Often circular patches, sometimes with yellow/orange "smoke ring" at edge. Can kill rapidly in warm, wet conditions.

Confirm Chinch Bugs: Soap Flush Test

1. Mix 2 tbsp liquid dish soap in 2 gallons water.
2. Pour over 1 sq yd at green/brown transition zone.
3. Watch 5–10 minutes. Chinch bugs (black with white wings, red nymphs) will surface.
4. Repeat 10–14 days after treatment to confirm control.

If Chinch Bugs Confirmed

• Treat with bifenthrin (Talstar) or fipronil granules per label.
• Check irrigation—dry spots attract chinch bugs.
• If enough live runners remain, grass may fill in with water and light fertilizer (Milorganite).
• If >50% dead, resod or plug.

If Fungus Suspected

Reduce irrigation frequency; water early morning so blades dry by evening. Fungicides suppress but don't eradicate. Cultural correction is essential.

Moss-Like Weeds

Indicate excessive moisture/shade. Address drainage and irrigation.

Bottom Line

Don't resod until pests are controlled. Soap flush, treat if needed, then assess regrowth potential.