Objective Bait broadcasting is currently the primary method for controlling Solenopsis invicta. This study evaluated the impact of different application methods and habitats on the efficacy of baits in controlling S. invicta, aiming to provide crucial data support for the scientific application of baits and the efficient control of S. invicta.

Method The time taken by S. invicta to transport bait formulations under different bait-broadcasting methods was recorded using the continuous photography method. The number of worker ants and ant nests in difference habitats before and after bait application was investigated and counted according to the methods specified in the Guidelines for quarantine surveillance of S. invicta Buren (GB/T 23626—2009).

Result Different bait application methods significantly affect the transport efficiency of S. invicta towards baits. When baits are directly applied to the surface of ant mounds, worker ants take an average of 101.5 minutes to transport all the bait, whereas when bait is broadcast in a circle around the ant mound or in segments, the average time taken by worker ants is below 70 minutes. The study also showed that different broadcasting methods did not affect the control efficacy of baits against S. invicta. Habitats significantly influence the control efficacy of broadcasting baits between rows on S. invicta. After a single equal-amount broadcasting of baits between rows, the average reduction rate of worker ants in cornfields reached 90.28%, significantly higher than that observed in sugarcane fields (51.34%). Following a supplementary application, no significant difference in worker ant reduction rates was detected between the two habitats. Upon the initial application of indoxacarb bait across five different habitats—wasteland, wax apple orchard, grassland, macadamia-nut orchard, and lemon orchard—the reduction rate of active ant nests consistently surpassed 98% in every scenario. In contrast, following the first application of spinosad bait in fishponds, the reduction rate of active ant nests reached 55.82%. For indoxacarb-based baits, the reduction rates of active ant nests after the first application exceeded 98% across all five tested habitats. In three specific habitats—wasteland, wax apple orchard, and fishpond—the density of active ant nests recovered to 2.29, 2.31, and 5 per 667 m², respectively, by the 155th day following the initial bait application. In contrast, the density of active nests in grassland, macadamia-nut orchard, and lemon orchard remained consistently below 1 per 667 m² throughout the same monitoring period.

Conclusion The bait-broadcasting method does not affect the control efficacy of baits against red imported fire ants. Habitat is significant factor influencing the control efficacy. When using baits to control S. invicta, long-term monitoring and timely supplementary applications should be carried out to reduce bait consumption and achieve optimal control results.