Proceedings of the Vertebrate Pest Conference

There are five species of meadow voles found in California. The two that are most economically important are Microtus californicus and Microtus montanus. Meadow vole populations are extremely cyclic, reaching a peak every four to six years. During these periods when the vole population is increasing in numbers, damage to crops like alfalfa, artichokes, potatoes, and sugar beets can occur. The best time to survey for vole activity is before the crop is planted. The grower or farm operator should look for vole activity in grassy borders around the crop or along roadsides and ditch bank areas. Snap-trapping may also be used to confirm the presence of voles. Clean cultivation and weed control on grassy borders adjacent to crops will help reduce potential harborage for voles. A small or localized vole population on a crop border is much easier to control than if the voles become established in the crop. Rodenticide-treated baits are very effective in reducing vole populations. Bait distribution may be done by spot-baiting, placing bait by hand, or by broadcasting, scattering bait over the entire infested area.