Safer & More Effective Ant Insecticides
By Mika Pringle Tolson
UC TSR&TP Trainee Linda Hooper
Have you ever wondered how to get rid of those pesky ants in your kitchen? First you try all of the latest non-toxic remedies: lemons, garlic, baby powder, cooking spray, borax, cinnamon. Then you resort to poisons, but nothing seems to work for very long. Why? Linda Hooper, a doctoral student in Entomology at UC Riverside is investigating this question by tracking the movement of toxicants in ant colonies. With a bachelor's in biology, and a master's in entomology studying ant biology - foraging, colony characteristics, and the reproductive cycle, she is well qualified for the job. Her doctoral research, supported in part by a TSR&TP graduate student fellowship, looks at the distribution and fate of the insecticide hydromethylnon in Argentine ants and the surrounding environment. Argentine ants are a cosmopolitan species, and in California they are the number one pest ant, especially around structures. Millions of dollars are spent annually trying to eradicate these ants, with surface sprays being the most common type of treatment. There are two problems with this approach: poison sprays can contaminate the environment, and it has been shown that their effectiveness is limited at best. Hooper explains, "The ants you see above ground are only about 10% of what's in the colony below. The typical levels of toxicants that are in commercial baits right now aren't killing the queens. Pesticides that are currently on the market are successful in suppression, and that should be the word that's used - suppression, and know when you use them that there's going to be a recurrence." Hooper is working to develop an effective liquid and granular bait to reduce the use of broadcast insecticidal sprays. She chose the toxicant hydromethylnon because "it is one of the most widely used toxicants in ant baits" and it is photolabile, readily broken down by sunlight, so it poses less of a threat to the environment than other insecticides. For her master's thesis, Hooper developed a granular bait that is highly attractive to ants. She hopes to use this bait in conjunction with the lowest effective concentration of hydromethylnon to develop a safer insecticide that really works. She is also studying the nutrient dynamics within colonies to determine how these baits are distributed by the ants. The future Dr. Hooper would like to continue her research in insect toxicology and nutrition and teach at one of the California State University campuses.
Argentine ant feeds froma tube in Linda Hoopers lab.
(Photo courtesy of L. Hooper)
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