The Efficacy of Milorganite® as a Repellent for Ground Hogs

The objective of the study was to evaluate the efficacy of Milorganite® as a repellent to mitigate damage on impatiens (Impatiens walleriana) by free-ranging ground hogs (Marmota monax). This biosolid byproduct of an activated sludge processing technique has been suggested as a repellent for a number of species. Three plots were established within 5 m of verified ground hog burrows at a feed and livestock working facility. Each plot consisted of three plastic containers with six impatiens plants per container. At each plot, containers were secured in drainage trays 2 m apart and received a topdressing application of 2500 kg/ha, 5000 kg/ha or 0 kg/ha equivalent of Milorganite® . Changes in plant area as determined by digital photographs taken on day 0 and day 7 post-treatment were used as an indication of consumption. During the 21-day trial, new plants were treated and evaluated at 7-day interval. Each week, order of plant treatments within each plot was rotated in an array to test for potential location effects. No differences (P > .10) in post-treatment plant area were observed between the treatments. All plants received damage. No differences (P > .10) in level of damage could be attributed to week of study, order of treatments within plot, between plot or technicians evaluating digital photographs. Based on these results Milorganite® did not appear effective as a repellent for ground hogs.