Proceedings of the Vertebrate Pest Conference

Warfarin, zinc phosphide, norbormide and alphachloralose have been microencapsulated by the technique of coacervation and fed to laboratory rats (R. norvegicus) and mice (M. musculus). Results are given of experiments in which the concentration of rodenticide, wall material, and phase ratio have been varied separately and in combination. Experiments are also reported in which normal and encapsulated rodenticide have been fed together in the same test diet. Microencapsulation can increase the intake of rodenticides, appreciably, whether or not alternative food is simultaneously available. Nevertheless, significantly higher kills from higher intakes of poison have not been achieved, indicating difficulties in optimizing the characteristics of the capsule wall to achieve the desired release of ingested active ingredient.