Resistance to Rodenticide Found in Meadow Voles in Artichoke Fields
What Has ANR Done?To help artichoke growers deal with this serious pest situation, UC wildlife experts conducted trials to find alternative control materials and strategies. In the laboratory, they studied the efficacy of zinc phosphide-treated artichoke bait on meadow voles and found it to be extremely effective. They also conducted trials in artichoke fields to compare the laboratory findings with those under field conditions. Zinc phosphide-treated artichoke bait was very effective in reducing meadow vole populations in the artichoke field plots. Overall effectiveness was 95 to 98 percent, compared to about 50 percent with chlorophacinone. The low persistence of zinc phosphide in the environment and the fact that it does not accumulate residue in the vole carcass makes it a viable rodenticide for voles in artichoke fields.
Alternative Rodenticide Found to Control Resistant VolesTo make this a useful solution, zinc phosphide must be registered for use in artichoke fields. Data from the UC trials are being used to support the registration of this material. Since this bait works in a completely different way than chlorophacinone, it will be effective on those animals that have developed the resistance we identified, giving artichoke growers a tool to reduce the serious damage to their crop. In the future, alternating treatments with zinc phosphide and anticoagulants like chlorophacinone will be an important strategy in fighting rodenticide resistance.
Supporting Unit: Wildlife, Fish & Conservation BiologyTerrell P. Salmon, Ph.D.
County Director and Wildlife Specialist
UC Cooperative Extension - San Diego