Evaluation of White-Tailed Deer (Odocoileus virginianus Raf.) Browse Preferences and Commercially Available Deer Repellents in Southern Landscapes

Abstract

Variation exists among landscape plant species browsed by white-tailed deer (Odocoileus virginianus Raf.) herds. Two experiments were conducted during February, 2011 and 2012 where browse damage was evaluated for Rhaphiolepis indica L., Rhododendron indicum L. ‘Judge Solomon’, Ilex cornuta Lindl. ‘Burfordii Nana’, Ophiopogon japonicus L. f., and Thuja occidentalis L. Tests were conducted inside a 430-acre high fence compound where approximately 100 adult free-ranging white-tailed deer were located, equating to approximately 150 deer per square mile. Twelve days after placement (DAP) in a mock landscape using container grown plants, Rhaphiolepis indica had the entire canopy removed both years. Rhododendron indicum ‘Judge Solomon’ had between ⅓ and ½ of its canopy removed during 2011, but less than ⅓ of the canopy removed in 2012 12 DAP. Ilex cornuta ‘Burfordii Nana’ was only slightly browsed during 2011 with no damage in 2012. Ophiopogon japonicus in 2011 and Thuja occidentalis in 2012 had no browse damage. Rhododendron indicum L. ‘Judge Solomon’ and Rhaphiolepis indica L. are two woody species found palatable to Odocoileus virginianus Raf. Both were recipients of chemical deer repellent applications during experiments conducted in February, 2011 and March, 2012. In Experiment 1, the repellents tested were PredaScent™, Deer Out™, Deer Stopper®, Plantskydd™, and Buck Off!. The control treatment was water. Thirty one days after treatment (DAT), there was no difference among the treatments, including the control, for browse damage rating or growth index (GI) for either species, with the plant species remaining mostly unbrowsed. During Experiment 2, Gold’n Gro® Guardian, Deer Out™, Deer Stopper®, and Buck Off! were tested. The control treatment again was water. At study termination 31 DAT, treatments were similar for browse damage rating and GI including the control for Rhododendron indicum ‘Judge Solomon’, with the plant species remaining unbrowsed throughout the study. Browse damage for controls was greater than all other treatments except the Gold’n Gro® Guardian for Rhaphiolepis indica. Although not severe, both treatments received browse damage while plants treated with Buck Off!, Deer Out™, and Deer Stopper® received no browse damage. There were no differences in treatment GI at 31 DAT. Begonia semperflorens L., Impatiens x hybrid L., and Catharanthus roseus L. G. Don were herbaceous species used in two similar repellent experiments during the spring/summer of 2011. Experiment 1 was initiated April 11th and the included treatments were PredaScent™, Deer Out™, Deer Stopper®, and Gold’n Gro® Guardian. The control treatment was water. Experiment 2 was initiated on June 3rd with the PredaScent™ treatment being omitted. Both experiments yielded no differences due to treatment for all species including the control for browse damage rating. Mean damage ratings for all treatments and species remained at zero during the first test except control treatments on Impatiens x hybrid which had a 0.125 rating 14 DAT. Mean browse damage ratings of all treatments and species remained at zero for the duration of the study in Experiment 2. Experiment 1 had no treatment differences for GI 31 DAT, although in Experiment 2, the Gold’n Gro® Guardian treatment on Begonia semperflorens was different from all other treatments 31 DAT, having a lower mean GI than the other treatments.