Apply barrier spray to yard vegetation

What to Do

Spray the undersides of leaves, shrubs, tall grass, and shaded resting areas around the yard with a residual insecticide every 3-4 weeks during mosquito season. Common active ingredients include lambda-cyhalothrin, permethrin, and bifenthrin (pyrethroids).

Why It Works

Adult mosquitoes rest in shaded vegetation during the day. Barrier sprays create a treated zone that kills mosquitoes on contact when they land on treated surfaces. The residual effect lasts 3-4 weeks before reapplication is needed. Natural alternatives include cedarwood oil and garlic-based sprays, though these last only about 10 days.

Tips

• Pyrethroids are toxic to fish and aquatic invertebrates — do not spray near ponds, streams, or storm drains
• Toxic to cats at high concentrations — allow sprays to dry completely before pet access
• Professional barrier spray service: $75-150 per visit, 5-7 treatments per season
• DIY products: $15-40 per application
• Barrier sprays should supplement larviciding, not replace it