Proceedings of the Vertebrate Pest Conference

Field rodents such as common voles cause significant pre-harvest damage during population outbreaks in European agriculture, and commensal rodents such as house mice are of concern worldwide. Usually, rodenticides are applied to minimize damage by these species. Rodenticides are not species-specific and may cause environmental problems. Plant secondary metabolites (PSM) could be used as a tool for sustainable rodent control, potentially minimizing damage and environmental risk. We screened volatile PSMs in feeding trials and in enclosure trials to identify if the odor of herbal substances repelled the target species. In feeding trials, the odor of two PSMs considerably reduced food intake in both rodent species. The use of underground chambers in enclosures indicated three repellent odors were effective for house mice, based on visitation rates of these rodents. Common voles visited the chambers equally independent of treatment and hence showed no avoiding behaviour. Further PSMs, combinations, and varying concentrations will be screened to support development of products. Effective repellents could be used to treat commodities to be protected from rodents and to develop an “odor barrier” against common voles to reduce migration from refuge areas to crops. Our preliminary findings suggest species-specific effects of some PSMs (impact on common voles but not on house mice, and vice versa); this may offer an option to repel unwanted species. Our results contribute to the development of non-lethal management tools for rodent pest species that are potentially more target-specific than traps or rodenticides.