Landscape and Nursery - Deer Management

The following are non-lethal approaches to deer management in nurseries and landscapes.

Fencing

Fencing is the most efficient long-term solution to a serious deer damage problem. However, fencing is also expensive. Some innovative new products and fence designs are making exclusion of deer from crops both cheaper and more effective. Development of high-tensile steel wire, high voltage pulse generators and 5-7 strand vertical designs seem to offer effective protection at reasonable cost. Some deer may penetrate fences, but these usually are easy to deal with or tolerate. The new fences are far cheaper than genuine deer-proof fence (8-10 foot woven wire). Your county Extension agent can provide a list of fencing contractors and suppliers.
An inexpensive, temporary electric fence is valuable for some deer problems during snow-free seasons. This fence works by inducing deer to touch nose or tongue to the fence. The deer is shocked and thereafter avoids the fence. This fence is constructed using a single strand of 19- or 20-gauge smooth wire that is 2.5 feet from the ground. Enough 4-foot wood or electric fence posts are needed to maintain 50-foot spacing; usually these must be fitted with electric fencing insulators. Aluminum foil in 3 x 4 inch pieces is taped to the wire at 3-foot intervals and a 50:50 mixture of peanut butter and peanut oil is spread on the underside of the foil flags and on the tape. A 6-, 12- or 110-volt charger is then hooked to the wire. Obviously, deer can jump over or crawl under this fence, but once shocked they rarely do so. To ensure that a deer is shocked on the first approach, the peanut butter bait must be periodically renewed as it weathers, and the charger must remain connected and functioning effectively (free from shorts caused by weeds, especially).

This fence is easy to set up and easy to dismantle and move. Growers who cannot economically justify the costs of a 5-7 strand high-tensile fence, such as some Christmas tree growers, may find this single-strand fence a practical solution to their damage problem.

Repellents

The scientific data available for repellents are few and unclear. Hinder, Big Game Repellent (BGR), and thiram-based products show promise, with a number of important "ifs": if the deer population is not high, if the deer have good to excellent food in natural habitat, if the crop is not a highly preferred food to deer, if the crop is not surrounded by ideal deer habitat, and if the repellent is registered for the crop when damage normally occurs.
Some growers have reported success with human hair, lion or other predator dung, soap, Difolatan fungicide, "hot sauce," tankage, blood meal, bone meal, feather meal and a number of ingenious home concoctions. Our research indicates that there is no consensus among growers. Some believe that a certain repellent is remarkably effective, while others growing the same crop are equally sure that the repellent does not work at all. Research done in New York and Pennsylvania shows that some repellents can provide an economic net gain if they are applied according to label specifications; at least one commercial repellent is thought by a field researcher to damage crops if not applied according to directions. However, be aware that repellents may wear off fairly quickly and require frequent re-application, may be effective for only a short time, and may be expensive in time and dollars.

Much of the effect of repellents is due to neophobia, fear of anything new, found in all wild animals. You can use this fear to good advantage by inserting something new in your production area, such as old rags soaked with strange scents or aluminum pie pans that flutter in the wind. Any repellent effect will probably not last long, so you will have to time your initial application to before the beginning of serious damage and continue to think of new sights, sounds and smells. No repellent or fear is likely to deter really hungry deer.

Mechanical Exclusion

An alternative that has received little attention is mechanical exclusion of deer from individual trees. It would be logical to use mechanical exclusion with long-lived and valuable plants that are especially vulnerable when young. Three or four steel fence posts or sharpened 2x4s driven into the ground around the young tree will deter bucks from rubbing. A cylinder of mesh wire around the tree would protect it from deer feeding until tree shape and scaffolds are adequately formed. Either of these alternatives would make routine maintenance more difficult. Both would incur costs in time and dollars, which might be offset by judicious scrounging of materials. Conversely, materials could be re-used many times.

From the Factsheet "Control of Deer Damage in Tree Plantations" by Thomas W. Townsend, School of Natural Resources, The Ohio State University