Laboratory evaluation of new insecticides and bait matrices for the control of leaf-cutting ants (hymenoptera, formicidae)

Abstract

AbstractLaboratory evaluation of alternative insecticides to replace persistent organochlorines in leaf-cutting ant baits is described, based on tests of 40 candidate compounds which were bioassayed with Atta cephalotes (L.) and Acromyrmex octospinosus (Reich). Insecticides having a suitable delayed killing action are listed, together with others which, although highly toxic to ants, had too rapid an action, but could feasibly be modified by using a controlled-release formulation.A search was also made for alternative bait matrices to replace the expensive and often inadequate materials in current use. Horticultural grade vermiculite with sorbed orange juice as an arrestant was the best matrix tested, being at least as attractive as dried citrus pulp, which was the best previously known matrix.Treatment of dried citrus pulp bait with propionic acid gave considerable protection against moulds, which spoil stored baits and baits placed in the field, and did not alter the attractiveness of these baits to ants.