| Abstract: | The effectiveness of two poison bait formulations was examined in trials against infestations of Mus domesticus in farm buildings. Treatment was extensive on each of four farms, covering all buildings and lasting 1 year. In the four trials, bait containing calciferol and warfarin in combination, or difenacoum was used. Mouse infestation level was monitored, using the mark-recapture trapping technique, before poison-baiting was begun and every 6 weeks thereafter. Poison bait consumption was high initially and mouse numbers were substantially reduced on all four farms within 6 weeks. Subsequently, the difenacoum treatments were the most effective in keeping infestation levels extremely low. Mice still resident when the treatments were terminated were removed by live and kill traps. Laboratory feeding tests were conducted on the live-caught survivors; all animals died after consuming poison bait of the kind used in the trials. Additional live-trapping, 6 months and 1 year later, produced evidence of recolonization and of renewed population growth. It is concluded that sustained control effort is needed to prevent the build-up of M. domesticus numbers in farm buildings. |
