University of Illinois Extension

Evaluating Damage and Potential Solutions

Farmers and Other Agricultural Producers

To implement the appropriate abatement techniques, it is necessary to properly identify the species of wildlife responsible for crop damage. Purdue University has an excellent website that helps agricultural producers determine whether crop damage was caused by deer. You can access the website at: http://www.agriculture.purdue.edu/fnr/cropdamage/wildlife/deer.htm

Nurseries, Vineyards, and Specialty Crop Producers

As the dollar value of the plants or commodities produced increases, it is important to carefully examine adequate deer exclusion as a long-term investment in protecting these products. In addition, proper inspection and maintenance of fencing is critical to exclude deer and other wildlife from an area. The Internet Center for Wildlife Damage Management provides several good designs for exclusion fences. Coupled with frightening techniques (such as scarecrows and motion detection sprayers) and regulated hunting (where possible), good fencing designed to exclude deer is perhaps the best method to achieve adequate damage management for high value crops. Frightening techniques are generally used to protect small areas such as garden plots.

Landowners and Homeowners

A deer browse line evident in a Arborvitae hedge. Photo courtesy of the United States Department of Agriculture.

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Deer leave many signs that they are in an area including droppings, tracks, beds (resting areas), antler rubs, browse lines, and other damage to plants. Deer often nibble off the tender shoots, twigs, or leaves of trees, shrubs, and other plants with their lower front teeth.

It is fairly easy to identify browsing caused by deer. Deer do not have teeth in the front of their upper jaw and do not have sharp incisors like rabbits. Instead of neatly clipping the vegetation at a 45° angle the way that rabbits and rodents do, deer twist and pull the plant when browsing. Deer can also browse much higher up on plants than rabbits. Browsing caused by deer typically gives the vegetation a shredded appearance. During the winter, when other foods are not available, deer may strip bark from shrubs and trees.

Exclusion

This photo shows damage caused by rabbits. Notice the cleanly angled cuts. Photo courtesy of Dan Ludwig, Illinois Department of Natural Resources.

Exclusion, using various types of fences, is probably the best way to control deer damage in certain situations. Some of these fences are very effective and provide almost total control. In general, the more effective fence designs are more expensive to construct and maintain. Simpler and less expensive fence designs may not provide complete damage control, but may be used on a seasonal basis to provide a satisfactory outcome in some situations. Proper inspection and maintenance of all fences is a critical part of their long-term effectiveness.

Exclusion can be a good option when the value of plants being protected is high or when a small area needs to be protected from deer, but large-scale installation of permanent fencing can be quite expensive. White-tailed deer are excellent jumpers. Permanent fences need to be at least 8-feet high to keep deer out of an area. Electric fences can also help minimize deer damage. They provide a significantly less costly alternative to solid fences and can be erected seasonally prior to predicted deer damage. There are a number of possible fence designs depending on the size of the area to be protected and the population of deer in the area. Specific fence designs can be obtained from your local IDNR District Wildlife Biologist.

This plant was eaten by a rabbit. Unlike deer, rabbits leave a clean cut.Photo courtesy of Dan Ludwig, Illinois Department of Natural Resources.

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A visible grazing system electric fence might be used in situations where the area to be protected is small. This material is highly visible polytape. Deer can see it better than conventional wire fences because the material will move in a breeze, which attracts the deer’s attention to it. Peanut butter on aluminum foil ‘flags’ should be used to educate deer to its presence. The peanut butter trick will work with conventional electric fence wire as well.

Placing a 5-foot tall wire cylinder around a plant can protect individual trees or plants. Tree protectors such as Vexar, Tubex, plastic tree wrap, or woven wire cylinders can all help protect new plantings. Three 6-foot t-bar steel posts placed in an equilateral triangle around a tree can also be fairly effective even without fencing. Placing netting over bushes or other plants can also be used temporarily on a seasonal basis to deter deer. For more information about deer exclusion techniques, visit the Internet Center for Wildlife Damage Management.

Repellents

Repellents may temporarily reduce the damage that deer cause to vegetation, but will not eliminate it completely. The goal when using repellents is to control deer damage. Success is measured in the reduction, not the elimination, of damage. As with frightening techniques, repellents must be applied before a pattern of damage has been established. There are two types of repellents. Contact repellents are applied directly to the plants and repel by taste. Area repellents are placed in the general area, or directly on the plants being damaged, and repel by odor. They provide a very limited area of protection around the plants.

Repellents may prevent deer from eating the plant, but they will not deter damage caused by antler rubbing. Additionally, repellents can be expensive and must be reapplied as the plant grows and after heavy precipitation events. Always read and follow the label instructions of the product. Some repellents are not for use on plants intended for human consumption. To be most effective, it is best to start using repellents before damage begins.

Repellents marketed as being effective in deterring a variety of wildlife species tend not to be all that effective for preventing deer damage. Although no deer repellent is 100 percent effective, its effectiveness will be dictated by how regularly it is used (per instructions), how many deer are in the area, what other palatable food sources are available to the deer, and the palatability of the plants being protected. The following products were found to provide some protection from deer damage:

  • Deer Away® Big Game Repellent (powder or spray): The active ingredient in this product is putrescent whole egg solids.
  • Deer Away® Deer and Rabbit Repellent (Get Away Deer and Rabbit Repellent): The active ingredients in this product are capsaicin and isothiocyanate.
  • Plantskydd™: The active ingredient in this product is edible animal protein.
  • Bye Deer® Sachets: The active ingredient in this product is sodium salts of mixed fatty acids. To be fully effective, this product should be placed at the top of the plant so that rainwater that dissolves the product will fall onto plant surfaces.
  • Deerbuster's™ Sachet: The active ingredient in this product is meat meal and red pepper. To be fully effective, this product should be placed at the top of the plant so that rainwater that dissolves the product will fall onto plant surfaces.
  • Hinder®: The active ingredient in this product is ammonium soaps of higher fatty acids. This product is the only product approved for direct application to plants intended for consumption. However, this product was not as effective in trials as the products listed above.

Frightening Techniques

One of the keys to success with using frightening techniques is to take action at the first sign of a problem. It is difficult to disrupt a deer’s patterns of behavior and movement once they have been established. Frightening techniques vary but may include: gas exploders (follow all storage guidelines), aluminum pie plates that bang together in the wind, scarecrows, lights, lanterns, radios, motion sensors for radio or light devices, and dogs on leashes. The best results are obtained from utilizing a variety of these methods at the same time and changing them every couple of weeks. Frightening techniques can provide quick, effective relief of deer damage, but the control for each technique is usually temporary.

Home Remedies

Some people have had success in deterring deer browse by hanging bars of lanolin soap or bags of human hair around valuable plants. While bars of soap can be effective, the protection they offer extends only about three feet around the bar. Human hair, blood meal, and bone meal all weather very quickly and lose their effectiveness. Using human hair or bars of soap assumes that deer are afraid of people and associated scents. In urban and suburban areas where deer are habituated to people and their scents, these home remedies generally do not work.

Deer are capable of feeding on lower branches of trees and shrubs. In areas of heavy feeding, this causes browse lines. Photo courtesy of the Illinois Department of Natural Resources.

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Plants’ Palatability to Deer

If adding ornamental plantings to a yard, select plant species that are less susceptible to deer browsing. The Morton Arboretum has produced a list of plants that deer tend to avoid. Some of the plants that seem to be less susceptible to deer include ornamental alliums (Allium), daffodils (Narcissus), and wild ginger (Asarum canadense). Also try planting thorny, prickly, or smelly plants. This approach does not always work. For example, deer will eat the buds, blooms, and smaller stems of ornamental tea roses. They also eat raspberries, blackberries, and poison ivy. Plant boxwood or short-needle spruces instead of yews or arborvitae. Native Illinois plant species such as black-eyed susan and foxglove do not seem to be preferred by deer. For a more complete list of perennials that are deer-resistant, visit the Gardening with Perennials website. Pachysandra is a good ground cover, and ferns fair better than hostas.

Deer like to eat apples and cherries, so tree protectors or fences might need to be used to protect your fruit trees. Fruit trees can also be a deer attractant in another way—apples or other fruits left to rot on the ground can draw deer in, and then they will feed on other palatable plants nearby. If food is scarce due to a severe winter, or if the population of deer in an area is high, the deer will eat plants that they do not normally prefer and usually leave alone. A deer will eat just about any plant if it is hungry enough.

A white-tailed deer stretches to reach food in the winter. Photo courtesy of Adele Hodde, Illinois Department of Natural Resources.

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Natural Areas

When deer become too abundant, they can cause a decline in biodiversity (the number and variety of species of living organisms) in natural areas. The most immediate impacts of deer browsing are reduction in the height, vigor and reproduction of plants by the repeated removal of stems, leaves and flowering parts of plants.

Research has shown that deer can cause a reduced diversity of woody and herbaceous plants, modify vertical structure in the forest understory, cause the extirpation of certain palatable plant species, reduce the reproductive potential of rare plants, and negatively impact wildlife that need forest understory for forage, nesting and cover.

The Illinois Nature Preserves Commission’s white-tailed deer guideline provides direction for implementing deer management programs on areas in the Illinois Nature Preserves System. Illinois Department of Natural Resources district wildlife biologists can provide advice on the reduction of deer damage and the management of deer.