Anticoagulant Rodenticide in Paper Tubes for Control of Meadow Mice

A grain bait treated with an anticoagulant rodenticide (Prolin) and attached by an edible glue to the inside of water repellent paper tubes was tested for the control of meadow mice (Microtus pennsylvanicus) at Sturgeon Bay, Wisconsin, during fall, winter, and spring, 1964-65. In the laboratory, seven of eight mice that could choose other food ate an average of 9.7 g of Prolin-treated bait in 10 days and survived from 4-10 days. Eight mice given no choice ate an average of 8.2 g of bait and survived from 3-7 days. When eight mice were placed in baited caged areas around apple trees all activity ceased in 5 days. In orchard plot tests all trees escaped mouse damage in an area baited for 2 months. In an area baited 18 days, 11 percent of trees were damaged, compared to 39 percent in the unbaited control area. This study was conducted to determine the feasibility and effectiveness of using 5x 1? -inch water repellent paper tubes with an inner lining of bait treated with the anticoagulant rodenticide Prolin (0.05 percent warfarin and 0.05 percent sulfaquinoxaline) to control meadow mice in Wisconsin apple orchards. Wisconsin orchardists estimate they lose an average of 2 percent of their trees to meadow mouse injury each year. In some years entire new plantings of young apple trees are girdled by meadow mice during the winter. Grain or cut apple baits with zinc phosphide and strychnine, or endrin ground sprays have been used in recent years to combat meadow mice. According to the literature, these methods have shown varying degrees of success, but with questionable safety to wildlife populations (Garl ugh and Spencer 1944, Eadie 1950, Horsfall 1951:13, Spencer 1959:25, Mohr 1959, Fitzwater 1961, Wolfe and Durham 1963). This content downloaded from 157.55. 39.243 on Thu, 06 Oct 2016 04:44:32 UTC All use subject to http://about.jstor. org/terms RODENTICIDE FOR MEADOW MICE Libby and Abrams 513 Although the anticoagulants have been effective and have achieved a commendable record of safety in commensal rat and mouse control, they have not been used to control meadow mice outdoors. Because a single feeding of anticoagulant rodenticides is rarely lethal to mice, the use of such baits outdoors would require that the bait be applied repeatedly or that protected bait stations be set up and maintained to keep the bait fresh and palatable throughout the baiting period. To establish and service such stations has been considered impracticable in commercial orchards. The development of a water repellent paper tube provides a disposable "bait station" that makes it feasible to use anticoagulant baits in the field. The writers wish to acknowledge the helpful comments and suggestions made during this study by Donald A. Spencer, Chief Staff Officer, Animal Biology, Pesticides Regulation Division, USDA; Walter Dykstra, Research Staff Specialist, U. S. Bureau of Sport Fisheries and Wildlife; William Gusey, Pesticides Regulation Division, USDA, and thank R. S. Ellarson, Department of Wildlife Management, University of Wisconsin, for reviewing the manuscript. LABORATORY FEEDING TESTS Sixteen meadow mice trapped at the Gordon Orchard, Sturgeon Bay, Wisconsin, were received at the laboratories of the Wisconsin Alumni Research Foundation, Madison, on November 11, 1964. These mice were then individually housed in cages and fed whole kernel yellow corn, apples, and alfalfa hay. On November 23, eight mice were continued on this diet plus a Prolin tube on a free choice basis. The other eight mice received the Prolin tube only. The results of the laboratory feeding studies are presented in Table 1. Fig. 1. Caged tree at the University of Wisconsin Experiment Station, Sturgeon Bay.