Dust boric acid in wall voids and behind appliances

What to Do

Using a bulb duster, apply a thin, barely visible layer of boric acid powder in hidden areas where cockroaches harbor — behind refrigerators, under stoves, inside wall voids through outlet plates, under sinks, and in cabinet crevices. The layer must be fine enough that roaches walk through it rather than avoid it.

Why It Works

Boric acid particles adhere to the cockroach's body. When the roach preens, it ingests the powder, which acts as a stomach poison. NC State University research shows no documented resistance to boric acid after decades of use. It retains potency indefinitely while dry.

Tips

• Heavy accumulations repel cockroaches — apply thin, not thick
• Do not apply on shelves or counters where food is kept
• Best used in combination with gel baits for comprehensive control
• Low toxicity to mammals but keep away from food preparation surfaces
• Cost: $5-15 for a container that lasts months