The use of different types of toxic bait for sustained control of possums

Assessment of six types of toxic bait in replicated field trials demonstrated that baits containing 0.15% 1080 were the most cost-effective for initial control of possum populations. Possums surviving an initial exposure to either 1080, cyanide, or cholecalciferol baits would not eat lethal amounts of bait containing another fast-acting toxicant during the following 2.5 months. However, 'shyness' to 1080 or cholecalciferol baits in possums surviving initial control was overcome by using a slow-acting anticoagulant poison during maintenance control. Sustained control of possums is currently most cost-effective if baits containing 0.15% 1080 are followed at least 2 months later by baits containing 0.002% brodifacoum. Unlicenced operators can similarly achieve sustained control of possums at very low densities by using brodifacoum baits 2 months after initial control is undertaken with baits containing cholecalciferol.