Santilli, F., Mori, L. & Galardi, L. Eur J Wildl Res (2004) 50: 85. doi:10.1007/s10344-004-0036-1
The method used most extensively in Europe to prevent damage due to browsing of woody plants consists of shelter pipes made of plastic material or net. This system, however, is not practical for plants such as olive trees where it is desirable for the branches to develop more than the trunk. For this reason, in an area with a high deer (Dama dama) population, three liquid repellents were tested for their ability to prevent damage by cervids to olive seedlings (Olea europaea). Tree Guard and Eutrofit reduced the percentage of plants browsed with respect to the control by a statistically significant extent through the third week (54.5 and 40.9% reduction, respectively), while for Hot Sauce, the differences did not reach significance after the first week. Tree Guard and Eutrofit were also able to reduce the level of damage for the entire eight week period of the test, while Hot Sauce did not differ from the control in a statistically significant manner. The use of repellent substances such as Tree Guard and Eutrofit to reduce the damage caused by cervids to olive groves therefore seems a possible strategy under conditions of medium and low density of animals. Eutrofit was the most economical product from the point of view of cost effectiveness.