It's cold outside, ants smell tasty leftovers and your good home cooking, and they're ready to come marching in. Block their entry by caulking cracks (which also, of course, saves energy). Should they breach the outer defenses, be prepared with nontoxic tactics instead of nervous-system-wracking pesticides. Read on for tips on what to avoid, and safer alternatives.

Most conventional household insecticides contain pyrethroid, not to be confused with gentler natural pyrethrins. Pyrethroids are a possibly carcinogenic pesticide that caused liver damage and neurological effects in animal tests performed by the EPA (see pages 19 and 20 of this document). However, the U.S. Centers for Disease Control website notes that both pyrethroids and pyrethrins, in animal studies, have shown possible carcinogenic properties.  Fortunately, there are many less toxic, alternative remedies to indoor ant infestations, as follows.

Beyond Pesticides lists many nifty substances that deter ants. Black pepper, cayenne pepper, and regular chalkboard chalk placed at the ants’ entry points will keep them at bay, as will pans of soapy water placed under pet food bowls. If you sprinkle cornmeal around the perimeter of your house, ants trying to get in will eat it and get so thirsty they drink themselves to death. Some also swear by Dr. Bronner's peppermint castile soap, made with certified organic and fairly traded plant oils, but don't apply it to broad areas of floor, as it's slippery.

Or, make your own ant hotels. You'll need:  Borax (a mineral-based powder found in the laundry aisle of supermarkets), a solution of sugar dissolved in water, some Kleenex or toilet paper, and glass jars with screw tops, or small, clean cans or yogurt cups you can cover with wax paper and rubber bands. Place a little crumpled tissue in the bottom of each container. Mix equal amounts of Borax and sugar water, pour over tissue, cover container and poke holes (i.e., ant doors) in lid. Place out of children's reach.Not in a DIY mood? Borax-based ant bait traps abound at organic gardening sites such as Gardens Alive.

Readymade insecticides based on pyrethrin, distilled from crysanthemums, are listed at at the organic gardening site Planet Natural. Warning:  Most of these products are intended for use outdoors, not in the home, where insecticide sprays can linger and be inhaled in indoor air. Here's a product for indoor use against ants and other bugs that doesn't use pyrethrins. Please remember that even natural substances can be poisons, so follow precautions for pesticide use, and keep out of reach of children and pets.

If the above weapons don't rain on the ant parade for long, switch to straight boric acid, the active ingredient in products such as Drax and Bora-Care. According to the National Pesticide Information Center, boric acid is non-carcinogenic and non-accumulative in soft tissues or the environment. Like Borax, boric acid is made from naturally-occurring boron and showed low toxicity in human and animal trials, but Beyond Pesticides cautions that it’s still poisonous and should be kept away from pets and small children. Boric acid works for more serious infestations because it takes 3 to 10 days to cause death. Ants will bring the poison back to the colony in the interim, so instead of just killing individual soldiers, you’re attacking them where they live. Sprinkle boric acid in a shallow container and place on a countertop near ant trails but, as always, out of children's reach.

Nobody said pest control was pretty. Still think you need the conventional ant killer? At least make sure you’re not using the dusty old spray stuck in the back of the linen closet. Until 2004, many indoor pesticides contained the chemical diazinon, an organophosphate known to be toxic to aquatic life. The EPA ordered all diazinon to be phased out of non-agricultural use after December 31, 2004, so some of your older insecticides may still contain diazinon as an active ingredient.   

Ants are pretty cool critters, as any kid crouching on the sidewalk can tell you. They just need the occasional reminder to keep out of your space.

Story by Rachel Brown. This article originally appeared in "Plenty" in November 2008.

Copyright Environ Press 2008