Icing sugar is also called powdered or confectioner's sugar. It is finely ground sugar mixed with cornstarch, wheat flour or similar substance to keep it loose and flowing. It dissolves almost instantly. Borax is also known as boric acid or sodium tetraborate. Technically, borax and boric acid are not the same, but they work the same way against ants. It works as a stomach poison and is found in many commercial ant baits.
Sugar vs. Protein Baits
Borax and sugar baits will only work on sugar-eating ants. Ant species can generally be divided into two categories, grease-eating ants and sugar-eating ants. Knowing which type you have will ensure that you use the right bait. Liquid, sugar-based baits work best for odorous house, Argentine, rover, white-footed and small honey ants. Grease-eating ants such as pavement, fire and big-headed need protein-based baits. Pharaoh ants need protein-based hydramethylnon bait.
Finding the Right Formula
Figuring out the right ratio of food to borax is difficult. If you use too much food, the bait will take too long to kill the ant colony. If you use too much borax, the bait will kill the ants before they have a chance to distribute it throughout the nest. Texas A&M entomologist Bastiaan Drees recommends using a 1 per cent boric acid or borax solution, or 1/2 teaspoon, to 1 cup food. Colorado State University Extension entomologist W.S. Cranshaw recommends a stronger solution that 5 to 10 per cent borax. For the best results, use the weakest solution to start. If ant activity is not reduced within a week or two, add more borax to the bait.
Mixing the Bait
Mix 1/2 teaspoon borax or boric acid to 1 cup icing sugar in a resealable plastic bag. Measure out 9 teaspoons of the solution into a jar. Add 1/4 cup hot tap water and mix well. Store the rest of the dry bait in a cool, dark place until needed. Label the bag as poison. Ants can be finicky eaters. If icing sugar does not attract the ants, switch to mint-apple jelly, honey or corn syrup.
Placing the Bait
Place a couple cotton balls into several baby food jars. Punch several small holes into the lids of the jar and add enough bait to each jar to soak the cotton ball. Bait-soaked cotton balls can be placed on old lids or pieces of foil, but the jars keep it away from pets and children. Mark all the jars as poison. Place the jars in areas where ant activity has been seen, inside or outside your house. Refresh the cotton balls once a week or whenever they dry out. Do not place the bait directly on the ground.