An efficacy test of cholecalciferol plus diphacinone rodenticide baits for California voles (Microtus californicus Peale) to replace ineffective chlorophacinone baits

Authors

Gary W. Witmer, USDA-APHIS-Wildlife ServicesFollow
Rachael S. Moulton, USDA/APHIS, Wildlife Services
Roger A. Baldwin, University of California DavisFollow

Date of this Version

2014

Citation

International Journal of Pest Management, 2014, Vol. 60, No. 4, pp. 275-278. http://dx.doi.org/10.1080/09670874.2014.969361

Comments

U.S. government work.

Abstract

California voles cause damage to pastures and rangelands, orchards and nurseries, and a wide variety of field crops, including artichokes. The anticoagulant rodenticides (chlorophacinone and diphacinone) typically used for voles are becoming less effective in controlling their populations. Consequently, there is a need to identify new rodenticides that will have a high efficacy on California voles so that agricultural production losses to rodents can be substantially reduced. We tested a new formulation containing two active ingredients (cholecalciferol and diphacinone) as a control method for California voles. Both a pelleted bait and an oil-coated artichoke bract bait were very palatable and efficacious against wild-caught, captive California voles. Efficacy levels of 70%-80% were achieved in the two-choice feeding trials. Additionally, the days-to-death (5-6 days) were less than the time-to-death with anticoagulant only baits. We recommend that a field efficacy study be conducted with cholecalciferol plus diphacinone bait formulations to determine their field performance in the reduction of agricultural damage by California voles.