Proposed lime stone treatment as pest control fails for the leaf-cutting ant Atta sexdens rubropilosa

Abstract

The effect of lime stone in controlling the leaf-cutting ant, Atta sexdens rubropilosa Forel, was studied on the fungus reared by the ants and on their behaviour. In the field, lime stone was applied with a pump in nine colonies, which were compared with nine untreated nests. Nine laboratory colonies were used to assess the effect of lime stone on the fungus reared by the ants, both with and without ants. There was no significant difference in the survival between treated and untreated nests with lime stone, both in the field and in the laboratory, although the behaviour of leaf-cutting ants apparently changed in laboratory colonies. The application of lime stone on the fungus sponge without the ants rapidly led to changes in pH and mortality. The application of lime stone did not control leaf-cutting ants contrary to the results reported by other authors. The behaviour of ants may have contributed to the inefficiency of this method of control, because the ants actively removed the lime stone deposited on the fungus. We suggest that alternative control methods be rigorously tested before being recommended.