Chemical control of Acromyrmex lundi (Hymenoptera: Formicidae) in anthropic ecosystems

Abstract

Background: Leaf-cutting ants are pests in agriculture, forests and pasture and, usually, controlled with toxic baits. The management and control of leaf-cutting ants is complex as a consequence of its sociability and behavior. We tested three toxic baits with abamectin, fipronil and sulfluramid to control colonies of Acromyrmex lundi Mayr, 1865 (Hymenoptera: Formicidae), in two seasons: 'Spring 2020' and 'Summer 2020/21', in Argentina.Results: The percentage of effective bait carried in the spring was similar between treatments with 80%, 80% and 90% for those with abamectin, fipronil and sulfluramid. The ant flow of A. lundi decreased after toxic bait applications compared to the control through time in all treatments. This activity was higher in the spring than in the summer. The baits reduced the foraging activity of A. lundi from 5 to 96 days after application (DAA). Abamectin and fipronil baits controlled 50% and 67% of the nests in the spring, and 20% and 43% at 96 DAA in the summer. Sulfluramid was the best treatment, killing 90% of A. lundi nests. Conclusion:The baits decrease the foraging activity of A. lundi until 96 DAA, with total or partial death of its colonies varying between treatments. The ant symptoms with the sulfluramid bait appeared faster than with fipronil and may be a result of the low level of carry-over or differences in the chemical quality of the active ingredients.

Action mode of fipronil and sulfluramid in baits on Acromyrmex crassispinus (Forel, 1909) (Hymenoptera: Formicidae) in laboratory conditions

“…This was observed for workers of the ants Atta bisphaerica (Forel, 1908), Atta capiguara (Gonçalves, 1944), Atta cephalotes (Linnaeus, 1758), Atta laevigata (Smith F., 1858) and Atta sexdens rubropilosa (Forel, 1908) (Hymenoptera: Formicidae), which cut dicotyledons and grasses, with a control efficiency from 90 to 100% of their colonies (Zanuncio et al 1992;Laranjeiro & Zanuncio 1995;Forti et al 2003), and of Acromyrmex spp. (Sabattini et al 2022). However, the similar carry rates of fipronil and sulfluramid baits in field studies were, possibly due to the high-quality physical properties of both baits (Sabattini et al 2022).…”

“…(Sabattini et al 2022). However, the similar carry rates of fipronil and sulfluramid baits in field studies were, possibly due to the high-quality physical properties of both baits (Sabattini et al 2022). The percentage of bait carried also depends on its attractants, individual weight and mass and physical structure (Rudolph & Loudon 1986;Wetterer 1994;Roschard & Roces 2003) with this third parameter affecting transport speed.…”

“…The variations in the efficiency of fipronil is due to its heterogeneity in the transport (Sabattini et al 2022), even in controlled experimental conditions and this would bring problems in operational conditions of management programs of LCAs in forest plantations (Sabattini 2018). The low transport rate will increase the exposure to the bait in the field and thus increasing the impact on non-target organisms.…”