Management Practices for Reducing Deer Damage in South Carolina Agriculture

White-tailed deer (Odocoileus virginanus) are common throughout South Carolina. Deer numbers vary from county to county, and even vary within counties. Rural areas with abundant agriculture and intermittent woodlands tend to support the highest deer densities in the state. High deer densities in agricultural areas frequently lead to crop damage. Damage may occur in many crops, but the following are highly susceptible to deer damage: soybeans, corn, cotton, peanuts, oats, wheat, sorghum, sunflowers, peas, beans, squash, pumpkins, strawberries, leafy greens, apples, plums, peaches, pears, blackberries, muscadines, and grapes (McDonald and Hollingsworth 2013). Damage levels appear to be related to deer density and availability of quality native browse. In areas with high deer densities, available high-quality natural browse becomes limited or removed from the landscape. In response, deer rely heavily on agricultural crops to fulfill their dietary needs. Damage levels range from minimal to complete crop failure.

Agricultural producers have numerous management options for reducing deer damage in their operations. Practices include lethal and non-lethal techniques. Deer damage reduction programs that incorporate multiple management practices tend to be the most successful. Not all management options are practical for every field/situation. Management options that may be incorporated are described in the paragraphs below.

Habitat Modification

Deer are creatures of edge, meaning they prefer to travel and spend time close to where two or more habitats meet. Staying close to edges allows deer to quickly retreat to escape cover. Areas close to escape cover give deer a sense of safety, and they tend to spend more time in these areas. Understanding a deer’s affinity to edge can allow farmers an opportunity to reduce the appeal of their fields to deer. Narrow fields frequently experience deer damage. Where possible, increasing the width of fields can reduce the amount of time deer spend in these fields. Additionally, removing escape cover from areas surrounding fields can also reduce the amount of time deer spend in these fields. Remove forested windrows between fields, and never plant pines adjacent to agriculture fields. Again, the goal is to reduce the amount of edge and the availability of escape cover.

Exclusion

Exclusion can be an effective method of reducing deer damage in agricultural fields. Exclusion is typically conducted through the construction of fences or other physical barriers. Round hay bales can be arranged around the perimeter of fields to provide a deer barrier. Bales must be arranged tightly so that deer cannot slip through. Deer can easily jump hay bales, but they are hesitant to enter fields that they cannot see. Hay bales are tall enough to prevent deer from being able to see into the field. A more common method of exclusion is the construction of fencing. Numerous fence methods have been tested over the years, and all have pros and cons. Effective fences may be electric, single-strand, or woven wire. Several examples of deer fencing can be found at the Internet Center for Wildlife Damage Management. The most effective deer fences are constructed using woven wire more than 8 feet in height. Fences require maintenance, and that level of maintenance can be significantly increased when built close to wood lines. Wind, rain, and ice frequently cause limbs or trees to fall on fences. Repairs should be made swiftly, as deer can cause considerable damage to crops in a few nights. The ideal situation is to construct exclusion fences far enough from trees to prevent damage.

Frightening

Numerous technologies have been developed and deployed to reduce or prevent deer damage. These include pyrotechnics, exploders, flashing lights, water emitters, sound emitters, etc. Frightening can be effective when needed for only a short time. Unfortunately, frightening does not seem to work well under full growing season conditions. Deer readily become accustomed to the frightening method and ignore them. Utilizing several frightening methods in rotation during the growing season may improve their long-term effectiveness.

Repellents

Deer repellents have become a common addition to deer damage programs in South Carolina agriculture. The active ingredients of deer repellents vary from product to product. Deer repellents typically rely on taste and/or smell to prevent deer browsing. Others incorporate predator scents to scare away deer. Common components of repellents include oils (garlic, peppermint, fish, etc.), fatty acids, soaps of fatty acids, capsaicin, predator gland or urine, egg putrescent, animal fats, etc. The length of time a deer repellent application is effective varies among products and varies based on environmental conditions. Some products have 10-15 days of effectiveness per application, while others claim to provide season-long control from a single application. Growers should consult with the manufacturer regarding the proper application rates, timing, and length of application effectiveness. Like frightening devices, repellents can lose their effectiveness over time. Growers are encouraged to rotate repellents between applications to prevent deer from becoming accustomed to products.

Lethal Control

Reducing deer population densities not only reduces deer damage to agriculture but also improves the overall effectiveness of many other damage prevention/reduction methods. Many of South Carolina’s major agriculture production areas have deer densities near or above 100 deer per square mile. Deer densities at these levels can be expected to create substantial damage to agronomic crops. Ideally, deer densities in these agricultural areas should be maintained at 30 deer per square mile or less. Annual deer spotlight or camera surveys can provide farmers with good estimates of their deer densities, allowing them to make sound management decisions. Information on conducting spotlight and camera surveys can be found at the links below.

Conducting White-Tailed Deer Spotlight Surveys in The Cross-Timbers and Prairies Region of North & Central Texas

Estimating Deer Populations on Your Property: Camera Survey

Deer population reduction practices typically consist of recreational hunting and/or depredation shooting. Recreational hunting can successfully manage deer populations to the desired density. South Carolina has one of the longest hunting seasons in the US. There are multiple game zones in the state, with each having different season opening and closing dates. Depending on which game zone the farm falls in, recreational hunting begins (August-October) and ends January 1. Recreational hunting programs should focus harvest heavily on female deer. The link below from the National Deer Association explains rates of doe harvest regarding stabilizing or reducing a deer population. The specific number of deer that hunters should harvest depends on deer population estimates; typically, 30-50% of adult does.

How Many Does Can I Harvest?

If recreational hunting efforts are unable to maintain the deer density below 30 deer per square mile, agriculture damage is likely to occur. In South Carolina, deer depredation permits are available to farmers experiencing deer damage outside of the regular hunting seasons. Farmers must communicate the issue with the South Carolina Department of Natural Resources and have Law Enforcement verify the damage prior to issuing a permit. Information on permitting and contact information can be found at the link below.

Depredation Permits

Depredation permits may allow farmers or their representatives to harvest deer outside of the regular hunting season and regular hunting hours. Depredation removals can be conducted using a variety of techniques. Most depredation removal efforts are conducted at night. Depending on the details in the depredation permit issued, the farmer or his representative may be allowed to use night vision equipped firearms, thermal imaging equipped firearms, or standard spotlighting. It is imperative that those involved with nighttime depredation shooting put SAFETY FIRST. Prior to initiating depredation removal efforts, the planned removal area should be studied closely to identify any safety concerns. In areas where firearms are not practical, consider modern crossbows, archery, arrow guns, etc.

Integrated Pest Management

Deer problems on South Carolina farms are rarely solved with a single management technique. A successful management program can be developed using the techniques mentioned above. Maintaining a deer density at or below 30 deer per square mile is critical to the effectiveness of other damage prevention techniques. When possible, recreational deer hunting should be used to meet this population goal. When recreational hunting falls short, implement deer depredation permitted removal. Once densities are reduced, farmers can incorporate habitat modifications, exclusion, frightening, and repellent techniques to protect their crops.

Literature Cited:

1. McDonald, J. E. and C. S. Hollingsworth. 2013. Preventing Deer Damage. Center for Agriculture, Food and the Environment. UMass Extension Vegetable Program. University of Massachusetts Amherst.

Originally published 01/24