The red imported fire ant, Solenopsis invicta Buren, is a global invasive pest that poses a great threat to human health.It is of great significance to develop green, efficient, and durable repellent to against fire antand protect human.Different concentration of ethyl acetate, butyl acetate, and methyl isoeugenol were prepared to test their repellent effects, and their stability was also analyzed.The results showed that the three active compounds had significant repellent effects on fire ants which was in either the foraging state or the disturbed state.Indoor experiment showed that, 2 mg/mL, 4 mg/mL, 8 mg/mL butyl acetate, 4 mg/mL and 8 mg/mL methyl isoeugenol and 8 mg/mL ethyl acetate had prominent repellent effects on fire ant foragers within 60 min. In field conditions, 5% butyl acetate and methyl isoeugenol preparations had strong repellent effects on fire ant forager within 60 min. and 5% and 10% methyl isoeugenol had noteworthy repellent effects on disturbing S. invicta in a short time. The physicochemical properties of three 5% repellent preparations prepared in laboratory were analyzed. It was found that the two repellent preparations of ethyl acetate and methyl isoeugenol had high stability. In summary, the results showed that 5% methyl isoeugenol preparation had remarkable repellent effect and high stability on red imported fire ants, and had efficient and durable repellent effect under different indoor and outdoor environmental conditions, and was a better candidate for green repellent of S. invicta.

The red imported fire ant (Solenopsis invicta Buren) is an invasive pest that poses a serious threat to the ecological environment and agricultural production. Its foraging and bait-carrying behaviors have significant impacts on the effectiveness of bait-based control methods. To better understand the bait transportation patterns of S. invicta and provide a scientific basis for its management, field experiments were conducted with ant mounds of different sizes. A commercial bait formulation (Shujue ant bait, 0.1% indoxacarb) was applied to each mound, and the amount of bait transported by the ants was measured at 1 h intervals. The results showed that the amount of bait transported increased initially, then decreased, and finally ceased over time. The second hour after bait placement represented the peak transportation period, while transportation nearly stopped after 8 h. The daily maximum transportation amount increased with mound volume, basal area, and height, reaching a maximum value of 36.096 g when the mound volume, basal area, and height were 47623.3 cm³, 2551.3 cm², and 28 cm, respectively. Moreover, a significant positive correlation was observed between worker body length and daily maximum transportation amount. A mathematical model describing the relationship among mound size, worker body length, and daily maximum transportation amount was established, providing a theoretical reference for optimizing the efficiency of bait-based control strategies against S. invicta.