Fungus/Disease/Pests Troubleshooting Guide for Lawns

Clients often see yellowing, browning, or discolored patches in their lawn. First, identify whether it’s due to heat stress, frequent dog urination, or another cause—resodding can be costly if the root issue isn’t solved.

Try hand-watering the area in addition to running your sprinklers. Heat stress often shows up near sidewalks, driveways, or stonework where concrete retains heat, causing blades to thin and “needle up.”

If patches persist after a few days, suspect bugs, disease, or fungus. No improvement? You may have an insect infestation such as grubs, chinch bugs, or army worms.

• Grubs: Use Grub Ex if you find more than 5 grubs per square foot. In North Texas, grubs are active late May–late September, peaking late summer to early fall.
• Drench test: Mix dish soap and water, apply to lawn, and watch for chinch bugs popping to the surface. Chinch bugs are most active in DFW from late June–September.
• Army worms: Extremely destructive, active August–September—identify and treat immediately.

For fungus/disease prevention and treatment, de-thatch the lawn (not St. Augustine), then apply Bioadvance (blue bottle at Home Depot/Lowe’s) plus Disease Ex granules. You can apply both together or alternate weekly—always follow the bottle’s curative or preventative rates.

Important: Don’t apply products within 24 hrs of rain—or they’ll wash away. Check forecasts before treatment.

You can also search Google Images for terms like “chinch bug damage” to compare and help diagnose your issue.

If these steps don’t work, consult your local lawn maintenance company or visit your nearest SiteOne.