Proceedings of the Vertebrate Pest Conference

Vole populations in southern Idaho experienced a significant peak in 2009-10. Following 2010, a decline in the population was observed. However, in 2014-15, vole populations increased dramatically with more reported crop losses than in 2009-10. Reported crop losses for 2014-15 were 30% and higher. In extreme cases, producers experienced over 50% crop losses and removed fields from production. An Idaho producer tracked vole populations using a GIS/GPS mapping app and reported vole numbers of 200 and more per acre (per 0.4 ha). Increased vole populations significantly reduced yields in rangeland, alfalfa, pastures, and other agricultural crops. In addition, homeowners and gardeners experienced significant vole damage in lawns, gardens, and small acreage orchards. Hypotheses for increased vole populations include a series of mild, open winters allowing for higher winter survival rates and wet springs and falls that produced abundant vole forage and habitat. Voles have remarkable reproductive capacity, which further amplifies problems associated with these rodents. Extension educators and specialists have estimated average losses due to increased vole pressure in Idaho at 30% to 50% and higher in crops, pastures, alfalfa, and rangeland. If current climatic and management trends continue, populations may continue to increase. Knowledge and implementation of an integrated vole management program has become necessary to decrease damage to crops, pastures, lawns, and gardens. To address this significant problem, we informally tested several effective vole management methods. Information and data were collected on rodent biology and management techniques from existing literature and field observations. Voles are not a protected species in Idaho and can be legally managed on private and public lands. We have developed an integrated approach to managing these rodents through the use of monitoring for vole sign, habitat modification, protecting desirable plants, trapping and other mechanical control measures, and use of effective toxic baits. Lastly, we developed and implemented an integrated, multi-faceted vole education program for Idaho clientele that was critical to effectively manage increased vole populations.