University of California, Riverside researchers
may have found a better, more environmentally friendly way to stop the procession of Argentine
ants, which have been spreading across the United States for the past few decades, despite
pest control efforts. The Argentine ant is an invasive species that
has become a major nuisance in California and southern states, including Georgia, South
Carolina. Alabama, Mississippi, Louisiana, Florida, Tennessee and North Carolina. In
fact, a 2007 survey found that 85 percent of all urban pest control services in California
were focused on the Argentine ant. A common weapon for managing the Argentine
ant has been residual insecticide sprays, insecticides that remain effective for a length
of time after being sprayed on a surface. However, the downside of this tactic is that
the insecticides can find their way into water systems and harm some aquatic species.
Another common management technique is baiting, where the ants take food mixed with insecticides
back to their colony and then expose other ants to the toxins. This method is more environmentally
friendly, but it can be tricky to perfect because the baits need to be palatable, non-repellent,
slow-acting, transferable, and inaccessible to non-ants.
In an effort to improve the baiting technique, a team from the UC Riverside added ant pheromones
to the bait. They found that baits with pheromones reduced ant activity by 74 percent after four
weeks. Baits without pheromones reduced ant activity only 42 percent after four weeks.
The researchers used the Argentine ant pheromone (Z)-9-hexadecenal, which is inexpensive enough
that the researchers believe they could be an economically viable modification to existing
bait products.