Whitetails are creatures of habit--most use the same home range year after year. They also tend to establish one part of their home range for feeding and another part for resting. For instance, if deer establish an orchard as a source of food, they will habitually move into the area a little before sunset to feed, and move back to the woods before dawn to rest.
The natural food habits of deer depend on the time of year and the plant species available. During the winter months, deer consume evergreen and dry leaves, as well as dormant buds. In the spring and summer, they eat new growth on woody and herbaceous plants. From late summer to early winter, fruits and nuts comprise a large part of a deer's diet.
Deer cause damage to fruit plants year-round, but the most serious damage occurs in the winter months when the availability of natural foods is limited. Dwarf, semidwarf, and young standard fruit trees are the most susceptible because most of the tree is within reach of the deer. In winter, browsing on dormant terminal buds may lead to stunted or misshapen growth in standard fruit trees less than 3 years old. Browsing on fruit buds of dwarf and semidwarf trees may lower fruit production. In either case, severe winter browsing can reduce tree vitality and even cause death.
During the spring and summer, natural sources of forage are readily available to whitetails; however, they still might browse new growth on fruit trees and eat ripening fruit. In autumn, deer might continue to browse and eat fruit within the planting. Additionally, bucks can cause severe damage by rubbing their antlers on trees, which can result in broken limbs and girdling of the trunk if the deer removes enough bark.
The extent of deer damage can be monitored through direct and indirect observation. Deer might be "caught in the act" during their active periods in the evening and early morning. Indirect observation involves recognizing signs that deer leave behind.
Lacking upper incisor teeth, deer characteristically tear off vegetation, leaving jagged edges that identify browsed trees. In comparison, browsing by rodents and rabbits leaves a clean-cut surface. The height of the damage, however, might be the only factor necessary to eliminate any mammal other than deer. Another method for determining the source of damage is to search for tracks. Deer leave a distinctive split-hoofed track that can easily be seen in damp soil or snow. Monitoring your fruit plantings for damage is an important, ongoing process and the first step in a successful management plan.
White-tailed deer are classified by the Pennsylvania Game Commission as a game mammal. As such, they are protected. Deer may be harassed throughout the year, but harming deer is prohibited outside of the legal hunting season, unless your livelihood comes from growing crops or fruit.
In Pennsylvania, the white-tailed deer is a protected game species. The game commission is authorized to manage the size of the deer herd through regulated hunting of antlered and antlerless deer.
As a landowner, you should encourage hunting in your area, especially if your fruit plantings are subject to heavy deer damage. Posted areas serve as refuges for deer during the hunting season and might compound the damage to an orchard by concentrating the deer population. Before opening the area to hunters, make sure the orchard is a safe area for hunting. Consult your local wildlife conservation officer for information on opening your land to hunters, or on eligibility requirements for hunting.
Repellents are most effective when integrated into a damage-control program that includes fencing, hunting, and several types of repellents. Apply repellents at the first sign of damage to prevent deer from establishing a feeding pattern at the site. Area repellents include tankage (putrefied meat scraps), ammonium soaps, bone tar oil, blood meal, and human hair. Contact repellents work by taste and must be applied directly to the plant. These repellents work best if you apply them in the dormant season on dry days when temperatures are above freezing. Examples of contact repellents are putrescent egg solids, thiram, and hot pepper sauce (capsaicin). Remember that whenever you apply a commercial repellent, you are required by law to comply strictly with the label. Home remedies often have limited success.
Human hair can be obtained from a local barber shop and placed in small bags (cloth or plastic--if plastic is used, punch three to four holes in the bottom). Tie up the tops and hang them around the garden or individually in trees. Soap bars can be placed in individual trees. Blood meal and tankage can be hung around the perimeter of the planting, initially 20 feet apart and then closer together if needed. Place these items about 30 inches off the ground, about the average height of a deer. Remember, success depends upon early preventative monitoring, as well as on alternation of materials.
Repellents containing denatonium saccharide, such as Ro-Pel, have been found to be less effective. There is little evidence to suggest that the bittering agent, denatonium saccharide, works as a mammal repellent. These products are taste repellents that may only be applied to plants during the dormant season. Because they are taste repellents, the new growth in the spring is not protected. Denatonium saccharide, including Ro-Pel, is not approved for rabbits. However, it is an approved deer repellent.
Repellents have variable results--what works for one grower might not work for another, and success differs from year to year. Some repellents do not weather well and require repeated applications during the season. Also, if deer are very hungry and the area lacks other more palatable food resources, they might ignore the repellents. Success must be measured by how much the damage has been reduced since it is rarely eliminated. In areas where deer density is low and damage is light, repellents may be a cost-effective part of your IPM strategy.
Fencing deer out of the orchard is the most efficient way to reduce damage when deer density is high and damage is extensive. The conventional 8-foot woven-wire fence effectively excludes deer by forming a barrier around the orchard. The fence consists of two widths of 4-foot woven wire and 12-foot posts. To prevent deer from crawling under the fence, keep the wire close to ground level. Unfortunately, deer-proof fencing is expensive, but it is effective, long lasting, and requires little maintenance.
An alternative to barrier fencing is an electric fence. This type of fence is designed to change the deer's behavior. Although deer can easily jump an electric fence, they will instead try to go through or under it. An electric fence takes advantage of this behavior and successfully trains the deer to stay 3 to 4 feet away from the wires.
Researchers at Penn State have developed a low-cost, five-wire electric fence. Through tests conducted statewide, the design has shown to be an adequate means of deer control. The fence incorporates high-tensile steel wire; in-line wire strainers; and high-voltage, low-impedance energizers. High-tensile fence can absorb the impact of deer and tree limbs, thereby eliminating some of the problems associated with soft-wire fences. In addition to Penn State's five-wire fence, other high-tensile electric fence designs are available.
The disadvantages of electric fences include required high maintenance and regular inspections. You must maintain a 6- to 8-foot-wide mowed strip along the fence perimeter to discourage deer from jumping and to decrease the weed load on the fence. You must also regularly check the electric current to ensure that the shocking power is sufficient for turning the deer. The advantages include a relatively low cost and, when properly maintained, a long life.
Another method of deer control in orchards is the use of guard dogs. Deer quickly learn the extent of a dog's range if it is chained. But free-ranging dogs can deter deer from feeding in any part of the orchard. An electronic containment fence can be buried or placed on an existing fence. This will keep the dogs in the orchard but allow them free access to all areas. Most dogs will patrol the edge of their territory; therefore, a closely mowed strip along the fence line will enable them to patrol the entire area. Herding breeds are the most effective because of their natural tendencies to chase animals. Long-haired breeds may be more apt to patrol in colder weather and therefore come in contact with deer in more conditions than the shorter-haired breeds. Place dog houses and feeders near established deer trails if they exist in your orchard. This will increase the likelihood that the deer will come in contact with the dog. Place dogs in the containment approximately one month before damage is anticipated. This will allow the dogs to get used to the containment system and the area.
Deer damage management is a complicated issue with many alternatives that depend upon financial considerations and the amount of damage that can be tolerated. A combination of control methods such as fencing and repellents is most effective. If possible, opening your orchard to hunters after considering safety and zoning regulations is a good way to reduce the deer herd on your property.