Aerial baiting to control leaf-cutting ants (Formicidae, Attini) in Trinidad. I. The bait, its production, and the effects of weathering on attractiveness and persistence of toxicants

Abstract

A technique is described for the preparation of large quantities (up to 1100 kg) of plain and waterproofed leaf-cutting ant bait from dried citrus meal, soyabean oil and aldrin. Small amounts (500 g) were weathered in sun and shade during wet and dry periods in Trinidad and the acceptability of the bait to ants {Acromyrmex octospinosus (Reich) and Atta cephalotes (L.)) and the persistence of toxicants in it were assessed in laboratory tests. Methyltrichlorosilane was the most effective of three waterproofing agents tested. In the wet season, waterproofed bait remained acceptable to ants for at least 30 days whereas plain bait deteriorated in less than four days; in the dry season waterproofed bait was only marginally more attractive. In the wet season, Acromyrmex strongly preferred weathered waterproofed bait to fresh leaves, whereas Atta slightly preferred leaves to bait. In the dry season, Acromyrmex showed little preference between bait and leaves, whereas Atta strongly preferred bait. Over the period that the bait remained attractive to the ants it retained between one-third and two-thirds of the original aldrin in the form of aldrin and dieldrin.