Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/3/1996
Publication Date: N/A
Citation: Interpretive Summary: Past research has indicated that boric acid is not an effective bait toxicant against fire ants. Our studies have shown otherwise, and, additionally suggest why boric acid has failed in the past to control fire ants. First, we show that low concentrations of boric acid act as a delayed-action toxicant. Second, high concentrations of boric acid (e.g. 5%) in baits, besides acting too fast are not consumed as much as lower concentrations. Also, the carrier and food attractant of our bait is ideal for fire ants which predominantly feed on liquids. This information is important in the use of boric acid ant baits for fire ants as well as other pest ants.
Technical Abstract: A boric acid - sucrose water baits was evaluated in the laboratory for toxicity, consumption and efficacy in the red imported fire ant, Solenopsis invicta Buren. Over the dosage range from 0.02 - 1.0% boric acid, LC50s (95% CL) ranged from 1.27% (1.05 - 3.88%) at 3 days to 0.11% (0.09 - 0.13%) at 8 days. Amount of bait consumed was inversely related to the concentration of active ingredient. High concentrations of boric acid bait (5%) were consumed at a lower rate than the control (10% sucrose water). In large fire ant colonies exposed to four concentrations (0.25%, 0.5%, 0.75%, 1.0%) of boric acid bait continuously, workers and brood were reduced by 90% at 6 weeks. Implications of these results are discussed with respect to current formulations of boric acid ant baits.