TERRO Ant Dust is ready to use and kills on contact. Will not wash away in the rain. Kills fire ants and carpenter ants, boxelder bugs, cockroaches, crickets, firebrats, spiders, ticks, wasps and silverfish. 8 months of protection indoors or outdoors. For best results apply when between 65 - 80 degrees Fahrenheit. Allow up to 3-4 days to see maximum results.