In California, scientists at the University of California at Riverside have developed an ant bait made out of seaweed.
The hydrogel baits reduced populations of invasive Argentine ants by 40–68% after four weeks. A second treatment brought the ant population down 61–79%.
“A 70% reduction is really successful, especially considering we are not spraying an insecticide but instead using a very targeted method that is better for the environment,” says Dong-Hwan Choe, an assistant professor of entomology at UC Riverside.
The work focused on homes in urban areas. However, the hydrogels could be used in agricultural applications such as citrus groves. Traditional pesticides can cause environmental contamination and harm beneficial insects, and bait stations are costly to maintain.
“The hydrogels are applied on the ground where the ants forage. Once an ant finds the hydrogel, it drinks from the surface of it. It then goes back to its nest and shares the toxic liquid with nest mates. The ants also create a trail to the hydrogels that their nest mates will follow,” says Jia-Wei Tay, lead author. “The hydrogels are designed to be slow-acting, so it takes several days before the ants die. By that time tens of thousands will have ingested the liquid bait.”