Eastern Wildlife Damage Control Conferences


Date of this Version

February 1991


A series of bioassays was performed to evaluate the effectiveness of soap and soap components as deer (Odocoi virginianus) repellents. Sweet-corn plots protected with tallow-based soap bars, nontallow bars, and those sprayed with commercial repellent Hinder”, experienced significantly reduced browsing compared with untreated plots. Damage top protected with tallow-based soap was less than damage to nontallow soap plots, while Hinder”-treated plots had intermediate damage. In a second bioassay, 2 spray applications of soap were found to be as effective as soap bars in preventing browsing native vegetation over a 126-day period. The addition of perfume did not enhance the repellent effect of the soap sprays. Finally a range of individual soap components were evaluated on apple prunings for their repellent properties. All components pro at least limited repellent effects, and plots protected with tallow fatty-acid soap bars, commercial soap bars, and soap perfume significantly less damage than untreated plots. Tallow fatty-acid soap reduced damage significantly more than coconut fatty soap, and tallow appeared to be a major component responsible for soap's repellent properties. Soap-bar applications to newly planted apple trees were estimated to cost $94/ha (2.74 acre), and were less expensive than typical commercial repellent pro during the first growing season. However, growers should consider alternative repellents after that time, as soap's cod effectiveness decreased due to the small sphere-of-influence of individual bars, and the increased labor costs associated with applying multiple bars to individual trees. Growers using soaps should practice aggressive vole management, as field observation suggest soap-treated trees are more susceptible to vole damage.