Proceedings of the Vertebrate Pest Conference

The frequency of mouse plagues in grain-growing areas of Australia has increased since the advent of conservation farming practices. The increase has been particularly marked on the Darling Downs in Queensland where the frequency has trebled. Broad-scale monitoring is undertaken by the government to provide a general forewarning of plague. However, the authors found, from a questionnaire to farmers, that the incidence and timing of plagues is highly variable across the Downs. It is apparent that farmers need to monitor the numbers of mice on their properties at regular intervals if they are to undertake preventive management. Bait cards (pieces of paper soaked in canola oil) were tested as a method for on-farm monitoring. The average amount of each card eaten was significantly correlated with the density of mice, but because of the scatter of the data the authors recommend that the cards be used in conjunction with other signs of mice such as evidence of crop damage or of active holes and runways in stubble. Zinc phosphide bait was found to be a highly effective rodenticide if used at a time when food was scarce. If the bait receives registration, it would be a valuable tool to control mice in crops, especially prior to flowering. On the basis of these results, it was concluded that effective management of mice could best be achieved by minimizing food supply in stubble by efficient harvesting, regular monitoring, and by strategic baiting and stubble management when necessary.