Boric acid works as an ant killer for the Argentine ant, the Pharoh ant and the odorous house ant. Boric acid must be mixed with sugar water, jelly, honey or peanut butter to create an ant bait. The sweet elements attract the ants, and the boric acid kills the ants.
When ants encounter the boric acid ant bait, they carry it back to the ant colony and spread it to the rest of the ants. To create an ant-killing mixture with sugar, water and boric acid, mix 8 teaspoons of sugar with 1 cup of water, and then add 1 teaspoon of boric acid to complete the mixture.