Apply non-repellent perimeter spray (fipronil)

What to Do

Apply a non-repellent perimeter spray around the foundation exterior, focusing on the base of walls, around door and window frames, and where utility lines enter. Use products containing fipronil (Termidor) or imidacloprid — not pyrethroids, which repel ants and scatter colonies.

Why It Works

Non-repellent insecticides are undetectable to ants, so they walk through treated areas and transfer the active ingredient to nestmates through contact. This provides a colony-transfer effect similar to baiting. The residual barrier lasts 30-90 days depending on the product and weather exposure.

Tips

• Never use repellent sprays (most store-bought sprays are pyrethroids) — they scatter ants into new areas and interfere with bait effectiveness
• Perimeter sprays are supplemental to baiting, not a replacement
• Do not spray indoors near bait placements
• Reapply after heavy rain