Non-Toxic Ant Control

Q: How do I get rid of ants in my house?

A: The small black ants (Argentine ants) that commonly invade houses in California are hard to get rid of, but these basic steps usually work. The steps below are described in more detail in the next section.

• Remove the invading ants
• Remove the attraction
• Wipe up the ants’ foraging trails
• Set out ant traps with borax or boric acid based bait stations

If you can follow these steps religiously for 2-4 weeks, the ants generally cut their losses and move on to another, more easily accessible, source of food. At that point, the key to ant control becomes prevention: wipe up food spills immediately, wipe down food prep surfaces with soapy water, remove garbage frequently, clean food debris out of sinks, rinse well any dirty dishes left in the sink, sweep and mop floors regularly.

Even if you get discouraged, don’t resort to insecticide sprays, because they are useless: they kill only the 1% to 10% of the ants in a colony that are out foraging for food, leaving the rest of the colony intact and ready to take their place. Meanwhile you now have toxic chemicals dispersed in the air you breathe and filming the surfaces in the room that you, children, and pets are likely to touch.

NOTE: This guide addresses only the Argentine ant, the most common ant to invade houses in California. For handling invasions of other ants (carpenter ants, red ants, Pharaoh ants), see the BIRC publication listed in section 5 below.

1. FIRST STEPS

Remove the invading ants

You can use your vacuum to quickly get rid of the invaders already in your house. Vacuum them up, along with some cornstarch, so that they suffocate in the vacuum. If they’re nesting in a potted plant, take it outside and flood it several times. If they’re in the garbage can, empty it outside and wash it down with a citrus-based cleaner or a weak bleach solution (one part bleach to ten parts soapy water).

Remove the attraction

Food. Put the most ant-attractive food items (honey, sugar, sweet liqueurs, cough syrup, etc.) into the fridge or into jars with rubber gaskets and lids that close with a metal clamp. Unless the lid of a screw-top jar has a rubber seal, ants can follow the threads right into the jar – although a couple of layers of waxed paper (not plastic wrap) between the jar and the lid often work pretty well as a barrier, once the lid is screwed down tightly. Transfer other foods, such as cookies in open boxes, to containers with tight-fitting lids; put butter in the fridge. NOTE: paper and cardboard boxes are not ant-proof.

Pet food. Create a "moat" for pet food by placing the food bowl in a somewhat larger shallow tray or pie pan filled with water. Or feed your pet only what it will eat immediately, then wash the bowl.

Garbage. Put kitchen scraps into a tightly-sealed plastic container. Throw nonrecyclable food containers (plastic ice cream cartons, meat wrapping paper, etc.) in an outside trash can. Wash glass, tin, and aluminum food containers thoroughly before tossing them into an indoor recycling bin.

Kitchen counters, floors and cabinets. Using hot soapy water, wipe down kitchen and appliance surfaces where sticky hands or food spills may have left some ant-attractive residue: kitchen counters, floors, cabinet doors and handles, fridge handle, stove knobs, sides of toaster, blender, etc. Immediately mop up food spills and sweep up food crumbs.

Erase the ants’ foraging trails

You can try erasing the scent trail that the ants have laid down by using a citrus-based repellant, available at some grocery and hardware stores. Some people have found success with cayenne pepper and cinnamon as well.

Set out boric-acid or borax ant bait stations

Set out ant bait stations near the ants’ entry points and/or foraging trails, so that the ants find them quickly, ingest the bait, and carry it back to their nest, where they feed it to – and kill – the rest of the colony. Bait stations such as Drax, with liquid bait (borax or boric acid in sugar water), attract ants all year round, and the containers have been improved to make them more child- and pet-safe.
Bait stations with solid bait are convenient, because they can be placed under the edge of carpets or attached with double-sided tape to walls, but they’re only attractive to ants in the late winter and early spring, when the foragers are looking for solid food to feed the hatching larvae—adult ants cannot digest solid food.

We recommend that the active ingredient in the bait be boric acid or borax, because these ingredients are the least toxic to mammals and because they work slowly, allowing the forager ants to spread it to the queens and through the colony, before the foragers themselves die.
If you can’t find borax or boric acid bait in a local hardware or variety store, you can make it at home.

2. FOLLOW-UP STEPS

In addition to continuing the good sanitation practices mentioned at the beginning of this guide, you can take steps to exclude ants from your house by sealing as many entry points as possible: weather-strip doors and use caulking to fill gaps in window and door frames and around baseboards, pipes, sinks, toilets, and electrical outlets. Prune trees and shrubs away from exterior walls, to prevent ants using them as a bridge into the house. Because Argentine ants are attracted to moisture, seal leaks and fix leaky pipes.

3. RECOMMENDED PRODUCTS AND SOURCES

The following brands are examples of citrus-based cleaners commonly available in grocery, hardware, or variety stores:

• Citra-Solv (marketed for household cleaning)
• Orange Guard (marketed for pest control)
  

To combat Argentine ants in the house, we recommend the following ant bait stations, which contain borax or boric acid as the active ingredient:

• Drax (5% boric acid in a sugar solution)
• Enforcer (5% borax, 4% boric acid in a sugar solution)
• Terro-Ant Killer (5.4% borax in a sugar solution)

PRODUCTS TO AVOID

We do not recommend following ant bait stations, because the poisons they contain may kill the foragers before they can share the food with the rest of the colony, so that your ant invasion continues unabated.

Also, although these products contain very little of the poison, by using them at all we create a continuing market for them, thereby ensuring that they continue in the toxic waste stream, from their point of manufacture to their ultimate destination in landfill or – via garden runoff or household sewage – into our waterways and oceans.

• Grant’s Kills Ants (contains arsenic)
• Maxattrax, Pro-Control 1, or Pro-Control Dual Choice (these all contain sulfluramid, a respiratory inhibitor)
• Ortho, Raid, or TAT (these all contain chlorpyrifos, an acetylcholine esterase nerve poison)

You may come across another product packaged as sticks of chalk and labeled "Miraculous Insecticide Chalk" in English and Chinese. It may be available in Chinese variety or grocery stores, although it is illegal in the U.S., because it has not been registered and approved as an insecticide. We do not recommend using this product.

4. RELATED ECOLOGY CENTER MATERIALS

• Common Sense Pest Control –reference
• Golden Gate Gardening - Library

5. RESOURCE GROUPS

• Bio-Integral Resource Center (BIRC)
  510.524.2567
• Master Gardener hotline: 639-1371

6. FOR MORE INFORMATION

Call the Bio-Integral Resource Center (see section 5, above) to order a copy of their excellent publication on ants, which provides additional information about different common species of ant and their control inside and outside the house. A complete list of their publications appears on their web page.
Common Sense Pest Control, Vol. XV, No. 2 (Spring 1999): Ant Control