426 Deer Response to Selected Plant Extracts

Abstract

Feeding damage by white-tailed deer to vegetable and ornamental crops are often adverse to plant growth, and result in economic and aesthetic losses. While the efficacy of commercially available deer repellent products is questionable, plant extracts may provide an environmentally sound alternative to traditional chemical treatments. Commercially available plant extracts (Dusty Miller, peppermint, Madagascar periwinkle, wax myrtle, barberry, juniper, geranium, rosemary, lemon balm, and yucca) known to be unpalatable plants were chosen as treatments. Thiram and putrescent egg spray were used as positive controls along with a no-spray treatment. Gomphrena were grown off-site in trade gallon pots and used as test plants. Sixteen deer were confined in two 1-acre study pens at the Auburn Univ. Deer Research Facility. Feeding damage was recorded daily using a 0 to 3 rating scale corresponding to 1/3, 2/3, and complete destruction, respectively. All damage data were converted into percent damage. Barberry and wax myrtle extracts made gomphrena more palatable to the deer as feeding damage exceeded that of the untreated plants. However, lemon balm, rosemary, yucca, and peppermint provide some level of protection against feeding damage to gomphrena. Fifth-day damage ratings for these extracts were 37%, 35%, 13%, and 19%, respectively. Fifth-day damage for untreated plants was 40%. Peppermint and yucca extracts appear to be promising alternatives to thiram and putrescent egg-based products.