Overview of Damage Prevention and Control Methods
- Harvest crops as early as possible
- Use lure crops and deer-resistant plants
- For trees – woven-wire or plastic cylinders
- Electric on non-electric fences
- Gas exploders, pyrotechnics, and gun fire
- Guard dogs
- Putrescent whole egg solids
- Ammonium soaps
- Blood meal
- None registered
No toxicants are registered for control of deer.
- Regulated sport and managed hunting
- Cage traps
- Drop nets
- Cannon or raocket nets
- Dart projectors and chemical immobilization
Other Control Methods
- Chemical immobilization
- Fertility control
Damage Prevention and Control Techniques
Widespread habitat modification is not recommended for the control of damage caused by deer. Destruction of wooded or brushy cover to reduce numbers of deer destroys valuable habitat for other wildlife. Deer forage over a large area, so it is impractical to eliminate all food for deer in an area.
Harvest crops as early as possible to shorten the period of vulnerability to deer. Plant crops that are favored as far from wooded cover as possible to reduce the potential for severe damage. In addition, lure crops can be planted to attract deer away from highways and fields. The effectiveness of lure crops is variable and artificial food sources may eventually increase deer densities and problems. Specific recommendations are not yet available regarding plant selection, timing, and proximity of lure crops.
Damage to woody ornamental plants can be minimized by selecting landscape and garden plants that are less preferred by deer. In many cases, original landscaping objectives can be met by planting species that have some resistance to damage caused by deer. Several plant lists are available online, but none are fool-proof. Check with your local Cooperative Extension office for a list of deer-resistant plants for your area.
Fences may be the only way to minimize damage effectively where deer are abundant or crops are particularly valuable. Several designs are available to meet specific needs. Baited, polytape electric fences are simple, inexpensive, and useful for protecting garden and field crops during snow‐free periods. Deer are attracted to the fence by appearance or odor, and are lured into contacting the fence with their noses. The resulting shock is a very strong stimulus, and deer learn to avoid the fenced area. Permanent, high‐tensile electric fences provide year‐round protection from deer and are best suited to high‐value specialty or orchard crops. The electric shocking power and unique fence designs present both psychological and physical barriers to deer. Permanent woven‐wire fences provide the ultimate deer barrier. They require little maintenance but are expensive to build.
Consider the following points before constructing a fence.
- Assemble past knowledge of the area regarding past claims, field histories, and deer numbers and movements to help determine an appropriate abatement approach.
- Deer pressure reflects both the number of deer and their level of dependence on agricultural crops. If deer pressure in your area is high, you probably need fences.
- Crops with high market values and perennial crops where damage affects future yields and growth often require protection provided by fences.
- In general, fences are most practical for areas less than 40 acres. The cost per acre for fencing usually decreases, however, as the size of the area to be protected increases.
- Perform a cost‐benefit analysis. Weigh the value of the crop to be protected against the acreage involved, costs of fence construction and maintenance, and the life expectancy of the fence.
- Consult an expert, such as a fence contractor, to supplement the material provided in this module. Detailed manuals are available from most fence manufacturers and sales representatives.
Tree Protection Use Vexar®, Tubex®, plastic tree wrap, or woven‐wire cylinders to protect young trees from deer. Four‐foot, woven‐wire cylinders can keep deer from rubbing on tree trunks with their antlers. When using tubes, install a screen at the top to prevent entrapment of cavity‐nesting birds. Two‐inch, mesh rigid fencing, 5 feet tall, secured to posts can provide excellent protection against deer browsing. Heavy black plastic fences can be a suitable alternative for single trees or planting beds in urban areas.
Temporary electric fences provide inexpensive protection for crops during periods without snow. Fences are easy to construct, do not require rigid corners, and the materials are readily available. Install fences at the first sign of damage to prevent deer from establishing feeding patterns in your crops. Weekly inspection and maintenance are required.
The peanut‐butter fence is effective for small gardens, nurseries, and orchards up to 5 acres subject to moderate deer pressure. Deer are attracted by the peanut butter and encouraged to make nose‐to‐fence contact. After being shocked, deer avoid fenced areas. Cost, excluding labor, is about $0.11 per linear foot.
The following steps outline how to build a peanut‐butter fence.
- Install wooden corner posts.
- String a strand of 17‐gauge smooth wire around the corners and apply light tension.
- Set 4‐foot, 3/8‐inch round fiberglass rods along the wire at 45‐foot intervals.
- Attach the wire to insulators on the rods 2½ feet above ground level and apply 50 pounds of tension.
- Attach 3‐ x 4‐inch foil strips to the wire at 3‐foot intervals, using 1‐ x 2‐inch strips of cloth adhesive tape.
- Apply a 1:1 mixture of peanut butter and vegetable oil to the adhesive tape strips and fold the foil over the tape.
- Connect the wire to the positive (+) post of a well‐grounded fence charger.
For fields larger than 1 acre, it is more practical to apply the mixture of peanut butter directly to the wire. You can make a simple applicator by mounting a free‐spinning, 4‐inch pulley on a shaft inside a plastic ice cream pail. Fill the pail with a peanut butter‐vegetable oil mixture that has the consistency of very thick paint. Coat the entire wire by drawing the pulley along the wire. Apply the mixture once a month. Attach foil flags to the fence near runways or areas of high deer pressure to make the fence more visible and attractive. Check the fence weekly for damage and grounding by vegetation.
Various forms of polytape or polywire, (e.g., Baygard®, and Turbo Tape) are very strong and portable. Use these fences to protect up to 40 acres under moderate deer pressure. Deer receive shocks through nose‐to fence contact and they learn to avoid fenced areas.
The following steps outline how to build a polytape fence.
- Drive 5/8‐inch round fiberglass posts 2 feet into the ground at the corners.String 2 strands of polytape (white or yellow are most visible) around the corners and apply light tension (1 strand that is about 2½ feet high can be used).
- Use square knots or ½‐hitches to splice or secure the polytape to corner posts.
- Set 4‐foot, 3/8‐inch round fiberglass rods along the wires at 45‐foot intervals.
- Attach the 2 strands of polytape to insulators on the rods at 1 and 3 feet above
ground level and apply 30 pounds of tension.
- Connect the polytape to the positive (+) post of a well‐grounded fence charger.
- Apply 2‐foot swatches of peanut butter to the polytape every 6 feet where deer
presence is expected to be high.
- Check the fence weekly for damage by deer and grounding by vegetation.
Offset or double fences often are used in gardens, truck farms, and nurseries up to about 40 acres that experience moderate deer pressure. Deer are repelled by the shock and 3‐dimensional nature of the fence. Add wires if deer pressure increases.
The following steps outline how to build an offset or double fence.
For the outside fence:
- install swing corners where necessary (see the section on fence construction‐rigid brace assemblies);
- string a 12½‐gauge high‐tensile wire around the outside of the swing corners and apply light tension;
- set 5‐foot line posts along the wire at 40‐ to 60‐foot intervals;
- attach the wire to insulators on the line posts, 15 inches aboveground and apply 200 pounds of tension; and
- string a second wire at 43 inches and apply 200 pounds of tension.
For the inside fence:
- string a wire around the inside of the swing corners and apply light tension;
- set 5‐foot line posts along the wire at 40‐ to 60‐foot intervals;
- attach the wire to insulators on the line posts at 30 inches aboveground;
- attach all wires to the positive (+) post of a well‐grounded, low‐impedance fence
- charger; and
- clear and maintain a 6‐ to 12‐foot open area outside the fence so deer can see it. Maintenance includes weekly fence and voltage checks.
Vertical fences are effective at protecting large truck gardens, orchards, and other fields from moderate to high deer pressure. When deer attempt to go through the fence they are shocked or physically impeded by the spacing of the wires. Vertical fences use less space than 3 dimensional fences, but may be less effective at inhibiting deer from jumping. A wide variety of materials, spacing, and specific designs are available, such as the 7‐wire vertical deer fence. We recommend employing a local contractor.
The following steps outline how to build a 7‐wire vertical deer fence.
- Install rigid corner assemblies where necessary (see the section on fence construction‐rigid brace assemblies).
- String a 12½‐gauge high‐tensile wire around the corner assemblies and apply light tension.
- Set 8‐foot line posts 2 feet deep.
- Attach a wire to insulators at 8 inches aboveground and apply 200 pounds of tension.
- Attach the remaining wires to insulators at the spacing indicated in Figure 12 and apply 200 pounds of tension.
- Connect the second, fourth, fifth, and seventh wires from the top, to the positive (+) post of a well‐grounded, low‐impedance fence charger.
- Connect the top, third, and sixth wires directly to ground. The top wire should be grounded for lightning protection.
- Clear and maintain a 6‐ to 12‐foot open area outside the fence so deer can see the fence. Maintenance includes weekly fence inspection and voltage checks.
Permanent high‐tensile fences provide year-round protection from damage caused by deer. Many designs are available to meet specific needs and require strict adherence to construction guidelines. Frequent inspection and maintenance are required. High‐tensile fences are expected to last 20 to 30 years.
Use slanted 7‐wire deer fences where high deer pressure threatens moderate‐to‐large orchards, nurseries, and other high‐value crops. It presents a physical and psychological barrier to deer because of its electric shock and 3‐dimensional nature.
The following steps outline how to build a slanted 7‐wire deer fence.
- Set rigid, swing corners where necessary.
- String 12½‐gauge high‐tensile wire around the swing corners and apply light tension.
- Set angle braces along the wire at 90‐foot intervals.
- Attach a wire at the 10‐inch position and apply 200 pounds of tension.
- Attach the remaining wires at 12‐inch intervals and apply 200 pounds of tension.
- Place fence battens at 30‐foot intervals.
- Connect the top, third, fifth, and bottom wires to the positive (+) post of a well-grounded, low‐impedance fence charger.
- Connect the second, fourth, and sixth wires from the top directly to ground.
- Clear and maintain a 6‐ to 12‐foot area outside the fence so deer can see the fence. Maintenance includes weekly inspection and voltage checks.
Permanent woven‐wire fences are used for year‐round protection of high‐value crops subject to high deer pressure. They are expensive and difficult to construct, but easy to maintain. Before the advent of high‐tensile electric fences, woven‐wire fences were used most often to protect orchards or nurseries where the high value of the crops, perennial nature of damage, acreage, and 20‐year life span of the fences justified the initial costs.
The following steps outline how to build a woven‐wire fence.
- Set rigid corner assemblies where necessary.
- String a light wire between 2 corners and apply light tension.
- Set 16‐foot posts along the wire at 40‐foot intervals, to a depth of 4 to 6 feet.
- Roll out an 8‐foot roll of high‐tensile woven wire along the line posts. Attach 1 end at ground level to a corner post with steel staples.
- Apply 100 pounds of tension to the wire using a vehicle or fence strainers. Attach the wire to line posts and corner posts with steel staples.
- Repeat steps 4 and 5 as necessary around the perimeter of the fence.
- Attach 2 strands of high‐tensile smooth wire to the top of the fence to raise the height of the entire fence to 9 to 10 feet. Minimal maintenance is required. Inspect for locations where deer can crawl under the fence.
Tips for Using Fences
Materials The use of low‐quality materials to reduce costs will reduce the effectiveness and life span of the fence. We recommend the following materials:
- round fiberglass or treated wood posts;
- high‐quality galvanized wire and steel components (for high‐tensile fences, use 11‐ to 14‐gauge wire [minimum tensile strength of 200,000 pounds and a minimum breaking strength of 1,800 pounds]), tension springs, and in‐line tensioners;
- compression sleeves for splicing wires and making electrical connections;
- lightning arresters and diverters to protect chargers;
- high‐quality fence chargers (chargers must be approved by Underwriters Laboratories [UL]). We highly recommend 110‐volt chargers. Six‐and 12‐volt chargers require battery recharging every 2 to 4 weeks. Use solar panels in remote areas to charge batteries continuously. For high‐tensile fences, use high‐voltage, low‐impedance chargers only (5,000+ volts and current pulse duration of at most 1/1,000 second); and
- Gates should be electrified, well‐insulated, and practical for the type of farming operation. Gates range from single strands of electrified wire with gate handles, to electrified panel or tubular gates.
Fences must be properly constructed. Do not deviate from the guidelines for construction.
- Prepare fence lines before construction. It is easier and less expensive to install and maintain fences on clear, level runs. Minimize corners to increase strength and reduce costs.
- Ensure that the electrical system is well grounded at the fence charger and every ½ mile of fence line. To ground high‐tensile fences, drive 4 to 6 ground rods 5 to 6 feet deep and 6 feet apart. Connect the ground post of the fence charger and the negative (‐) wires of the fence to the grounding system. Such a design is especially useful with dry or frozen ground. A fence with all positive (hot) wires may be advantageous under average crop and soil moisture conditions. Consult with a contractor or expert regarding the best choice for your needs.
- Install the grounding systems and fence charger before fence construction. Energize completed parts of the fence when you are not working on the fence to gain early protection.
- Rigid brace assemblies (corners, ends, and gates) are the backbone of all high‐tensile fence systems. They must be entirely rigid, constructed of the best materials, and strictly conform to design guidelines. The single‐span brace assembly is the basis of all high‐tensile strainer assemblies, regardless of location in the fence or fence design. This basic design is then modified to create double‐“H” braces, swing corners, and gate ends.
- Allow wires to slide freely through insulators on fence posts. Flexibility is necessary to endure frequent temperature changes, hits by deer, and obstructions.
- Identify electric fences with warning signs at 300‐foot intervals or less.
Regular inspection and maintenance are necessary to ensure the effective operation and longevity of most fences. Control vegetation near fences by mowing or applying herbicides to avoid excessive fence grounding by weeds. Maintain a good cover of sod.
Keep the fence charger on all day and night. Check the voltage weekly with a voltmeter. Maintain at least 3,000 volts at the farthest distance from the fence charger. Disconnect the lower wires if they are covered by snow. In late fall and early summer, adjust the fence tension (150 to 250 pounds) for high‐tensile fences.
Take action at the first sign of a problem. It is difficult to break the movement or behavioral patterns of deer once they have been established. Use frightening devices and repellents when crops are most susceptible to damage (e.g., the silking to tasseling stages for field corn or the blossom stage for soybeans).
Gas exploders set to detonate at regular intervals are the most commonly used frightening devices for deer. They can be purchased from several commercial sources and may be available on loan from state wildlife agencies, as they are used frequently to control damage by waterfowl. To maximize the effectiveness of exploders, move them every few days and stagger the sequence of firing. Deer quickly become accustomed to regular patterns. Increase the level of noise by raising exploders off the ground.
Shell crackers, fireworks, and gunfire can provide quick, temporary relief from damage caused by deer. Equip mobile units with pyrotechnics, spotlights, and 2‐way radios. Patrol perimeters of farms and roads in fields at dusk and throughout the night during times when crops are most susceptible to damage. These tactics cannot be relied on for an entire growing season. Always take proper safety precautions and acquire permits and training, if necessary, when shooting from vehicles.
A guard dog that is restricted by an invisible fence system or physical fence can keep deer out of a limited area, but care and feeding of the dog can be time-consuming. A guard dog that is restricted by an invisible fence system or physical fence can keep deer out of a limited area, but care and feeding of the dog can be time‐consuming. Use 1 dog for up to 30 acres and 2 for up to 50. Free‐running dogs are not advisable and may be illegal.
A bio-acoustic frightening device called DeerShield was developed recently. It employs motion-activated sounds designed to frighten deer.
Repellents are best suited for use in gardens and on ornamental plants. High cost, limitations on use, and variable effectiveness make most repellents impractical on row crops, pastures, or other large areas. Success with repellents is measured in the reduction, not total elimination, of damage.
Repellents deter deer by taste or odor. They are most effective when applied to trees and shrubs while they are dormant. New growth that appears after treatment will remain unprotected until it is treated. Repellents may reduce the palatability of crops, and should not be used on any parts of plants that are destined for human consumption. Hinder® is an exception, as it can be applied directly on edible crops. Follow all requirements outlined on the labels, as most repellents are registered for application to non‐edible plants during the dormant season.
During the winter or dormant season, apply repellents on a dry day when temperatures are above freezing. Treat young trees completely. It is more economical to treat only the terminal growth of older trees. Treat to a height of 6 feet above expected maximum depth of snow.
The effectiveness of repellents depends on several factors. Rainfall will dissipate some repellents, so reapplication may be necessary after a rain. Some repellents do not weather well even in the absence of rainfall. Deer hunger and the availability of other, more palatable food has a great effect on success. In times of food stress, deer likely will ignore repellents. The best repellents tend to reduce damage caused by deer for 4 to 6 weeks under moderate feeding pressure.
Home remedies or other non‐regulated products should not be used for control of deer. Always follow the instructions on the label. The following discussion of common repellents is provided only as a survey of the wide range of formulations available. Repellents are grouped by active ingredient. Many other formulations are available for sale, and some have not been tested under controlled, replicated experiments. No repellent will stop damage caused by deer under all conditions.
Deer-Away® Big Game Repellent (37% putrescent whole egg solids) is an odor and taste repellent that has been used extensively in western conifer plantations. It is reported in field studies to be 85% to 100% effective. It is registered for use on fruit trees prior to flowering, as well as ornamental and Christmas trees. Apply it to all susceptible new growth and leaders.
Hinder® (15% ammonium soaps of higher fatty acids) is registered for use on edible crops. Apply it directly to vegetable and field crops, forages, ornamentals, and fruit trees. Effectiveness usually is limited to 2 to 4 weeks but varies because of weather and application technique. Re-application may be necessary after heavy rains.
Thiram (7% to 42% tetramethylthiuram disulfide) is a fungicide that acts as a taste repellent, most often used on dormant trees and shrubs. A liquid formulation is sprayed or painted on individual trees. Adhesives such as Vapor Guard® can be added to increase resistance to weathering.
Miller’s Hot Sauce® Animal Repellent (2.5% capsaicin) is a taste repellent that is registered for use on ornamentals, Christmas trees, and fruit trees. Apply the repellent with a sprayer to all susceptible new growth, such as leaders and young leaves. Do not apply to fruit-bearing plants after fruit set. Vegetable crops can be protected if sprayed prior to the development of edible parts.
Plantskydd® Animal Repellent is made from dried animal blood. It is available in powder concentrate or ready-to-use liquid. It is suitable for use on organic farms. Do not apply to plants destined for consumption.
No toxicants are registered for control of deer. The poisoning of deer for any reason is illegal and likely will not be tolerated by the public.
Effective use of legal deer hunting is the best way to manage populations. By permitting hunting, landowners provide public access to a resource, while simultaneously reducing damage by deer. The daily and seasonal movements of deer rarely allow for a single landowner to control all land used by deer; neighboring landowners should cooperate. Landowners, state wildlife agencies, and local hunters should reach agreement about a desirable level for the deer in an area.
Methods for managing deer in a specific area already exist in most states. Either-sex seasons, increased bag limits, antlerless only permits, special depredation seasons, and a variety of other management techniques have been used successfully to reduce numbers of deer to below levels achieved by “buck only” regulations. Bow hunting from stands can be an effective way to reduce the number of deer in urbanized areas where use of firearms is not appropriate or accepted.
Depredation permits issued by some states allow for removal of deer where they are causing damage during non-hunting periods. Some communities and landowners may use “Earn-a-Buck” or other managed hunts to control populations of deer. The removal of does is essential for reducing the number of deer and associated damage.
Herds of deer can be reduced dramatically through sharp-shooting over bait. Recommended equipment includes .223-caliber rifles and use of frangible bullets. Frangible bullets will penetrate the skull of the deer but not exit, thereby increasing safety. Properly placed head-shots will kill a deer instantly. Shooters should demonstrate the ability to hit a 1-inch target at 50 yards consistently before using this method. The use of night-vision scopes and sound-suppressed firearms will enhance effectiveness (where legal). Appropriate permits are necessary from state wildlife agencies.
In special ases, such as city parks, refuges, or neighborhoods where shooting is not accepted or safe, it may be necessary to capture deer. The following capture techniques require state permits, are time-consuming, and require specific training to prevent deer from injuring themselves.
Instructions on cage trapping deer can be found on a video entitled “Netted Cage-traps for Deer: Tips and Techniques.”
Drop nets, depending on size, can capture up to 20 deer at a time. Deer are baited under the net and when the desired number of deer are present, the net is triggered to drop on top of the deer. When deer are captured, especially in large numbers, it is necessary to secure the animals quickly to prevent injury and minimize capture myopathy. A field crew is needed to quickly secure and immobilize the deer.
The WCS NetBlaster™ shoots a 40‐ x 60‐foot net using compressed air. It is suitable for capturing multiple deer at a time. Use of cannon nets requires skill and training. The area should be prebaited for several days before attempting to capture deer.
Net‐guns typically are used from helicopters and require significant skill due to the high risk of injury to deer and personnel. Net‐gunning costs up to $1,000 per deer but can be very effective as capture rates approach 6 deer per hour for highly skilled capture teams.
Other Control Methods
Individual deer can be darted with special drugs designed for immobilization. The drugs are strictly regulated and their use requires special training and licenses for state and federally controlled substances.
Chemosterilants and immunocontraception drugs have been developed to reduce or eliminate reproduction in deer. The drugs are labeled by the US EPA, and are available to personnel with federal or state wildlife agencies. State permits may be required for use. Specificity, efficacy, and delivery of contraceptive agents continue to impede widespread usage. The use of contraception for control of herds will be best suited to urban parks, refuges, and other discrete areas. Surgical sterilization may be more cost‐effective in the long run because of high efficacy and the need to handle deer only once.