Efficacy of Milorganite® as a Deer Repellent

The objective of this study was to determine the effectiveness of Milorganite as a potential repellent to mitigate damage incurred to chrysanthemums (Chrysanthemum morifolium) by free ranging white-tailed deer (Odocoileus virginianus). Milorganite, the biosolids by-product left from the activated sludge process from the Milwaukee Metropolitan Sewer District, has had extensive use as an organic, slow releasing fertilizer and soil amendment in the past 80 years. Application of Milorganite as a top dressing, at three dose levels (1120 kg/ha, 2500 kg/ha, 5000 kg/ha) reduced damage (P \u3c .05) to planted chrysanthemums by white-tailed deer over the 35 day study. While not significantly different (P \u3e .05) compared to the lowest treatment level (1120 kg/ha), there was a trend toward a dose response effect as determined by analysis of plant area from digital photographs. Protection appeared to be directly related to the topical application of the deterrent to the plant with odor from adjacent treated and control areas within a plot having no measurable influence on reducing plant damage. Based on these results, Milorganite was determined to be effective at reducing plant damage by the browsing of free-ranging white-tailed deer