Comparing the efficacy of delivery systems and active ingredients of deer repellents

Abstract

Deer (Odocoileus spp.) occur across the United States and provide many desirable recreational and aesthetic opportunities. Unfortunately, deer foraging, particularly where population densities are high, can negatively impact agricultural resources or damage ornamental plants. Repellents are often regarded as a desirable approach to limit deer browsing. Although many products are marketed for use as repellents, the efficacy of these products in actually reducing deer browsing is varied. This paper reviews the results from efficacy tests we have conducted at the NWRC Olympia Field Station over the past several years as well as repellent work conducted by others. General efficacies of delivery systems and active ingredients incorporated in a variety of products are compared. Generally, products which have repeatedly demonstrated good efficacy in our trials are those products that produce sulfurous odors. These products have significantly reduced deer browsing for 8 to 12 weeks.