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Abstract
This publication suggests various management practices to help
prevent or control damage by deer to field crops, orchards,
landscapes and gardens.
Table of Contents
Introduction
This publication suggests various management practices to help
prevent or control damage by deer to field crops, orchards,
landscapes and gardens. Because every field, orchard, landscape, and
garden is different, there is no way any or all of these management
practices will achieve perfect deer control, but they should help
reduce the damage.
Usually, deer damage plants by browsing on new vegetation during
the growing season. However, when food is scarce, deer will eat just
about anything to survive. One of the reasons that deer are becoming
more of a problem in many parts of the United States is that their
numbers are increasing. An Associated Press article on October 15,
2000 stated:
The national deer population, now estimated at 25
million to 30 million, has been growing for decades. Not only have
deer adapted to encroaching suburbia, but they have benefited from
a series of mild winters, an increase in newly developed areas
being declared off limits for hunters and a decline in hunting in
some parts of the country . . . Some forecasters believe there
could be a point when the deer population will become so large it
just can't sustain itself. But no one knows when. "We're not
certain when it will max out," Curtis [wildlife biologist Paul
Curtis of Cornell University] said. "Deer populations are already
at densities a biologist wouldn't have dreamed of 10 years ago."
(Associated
Press, 2000)
The cost of damage by deer will vary greatly, according to the
crops and plants being grown in relation to the number of deer
browsing. In the article "Oh, Deer" in the June-July 2002 Farmer's
Digest, Jim Armstrong, associate professor and wildlife specialist
with Auburn University, explained that it is not uncommon for some
growers in the Southeast to have $20,000 to $30,000 in crop damage
(peanuts and cotton) during a crop year. He says:
It's a widespread problem in agriculture. The
problem is that it tends to be very site-specific. Depending on
the habitat around the field, one person can have no damage and
the next can have a lot of problems. Deer prefer a fragmented
habitat that consists of both woodland for cover and open
cropland. Farmers may notice more feeding near the edges of the
fields near woods, where the deer can feed without straying too
far from cover. (Mullen,
2002)
The USDA estimates that total deer damage from auto collisions
and crop and timber losses reaches at least $1 billion a year. (Mullen,
2002)
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Regulations and Assistance
Because deer are protected by game regulations in all states, as
well as all Canadian provinces, I strongly suggest you contact the
specific wildlife, natural resource, or conservation agency that
enforces your state's wildlife regulations before implementing any
deer control practice. Some state agencies have specific programs
for technical assistance or to compensate for deer damage. Other
states, or even local municipalities, may have laws restricting some
options for deer management. Producers need to keep current with
their state laws and regulations, because they can change from year
to year.
The Wildlife Services (WS), an arm of the Animal and Plant Health
Inspection Service (APHIS) charged with helping to prevent or reduce
wildlife damage, provides technical assistance or direct control.
For more information about assistance, contact any state APHIS
office. The address and phone number of each state's Wildlife
Services State Director and the state's Wildlife
Services activity report is available by calling the national
Wildlife Services Operational Support staff at (301) 734-7921.
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Management Practices
There are five general methods for preventing or controlling deer
damage to crops. These include exclusion, cultural methods, scare
devices, repellents, and culling or harvest. The referenced and
enclosed materials provide more detailed information on the use of
these methods.
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Exclusion
Several methods of exclusion are available. They can involve
permanent or temporary fences, a wireless deer fence, or other
methods of keeping deer from getting to the plants to browse.
Fencing
The most effective method for exclusion is a well-designed fence,
and there are several designs available to meet specific needs.
Temporary electrified fences are simple, inexpensive, and useful in
protecting garden and field crops during snow-free periods.
"Baiting" the fence with peanut butter, apples, etc. may enhance the
effectiveness of electrified fences. Deer are attracted to these
fences by their appearance or smell and are lured into contacting
the fence with their noses. This causes an effective shock that
trains deer (sometimes) 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.
Permanent woven-wire fences provide the ultimate deer barrier.
They require little maintenance but are very expensive to build. In
fact, the cost of constructing effective fences often limits their
use to areas of intensive agriculture, such as orchards or private
gardens.
The Cornell publication Managing White-Tailed Deer in
Suburban Environments: A Technical Guide states:
For a given deer density, the potential for damage
will often be greater on large plantings than smaller ones. (Caslick
and Decker, 1979; McAninch
et al., 1983) Consequently, large areas often require more
substantial fencing designs to achieve a level of protection
similar to small areas. Based on anecdotal reports and research
experiences in New York, vertical electric fence designs seldom
provide reliable protection for plantings larger than five acres
under intense deer foraging pressure. Slant-wire, electric-fencing
systems can protect plantings approximately 50 acres in size.
Blocks larger than 50 acres usually require eight-foot-high,
woven-wire fencing to reliably prevent deer from entering the area
if feeding pressure is high. (DeNicola
et al., 2000)
The same publication suggests that fencing systems such as the
baited electric wire, fences with three-dimensional outriggers, and
slanted and vertical fences up to 11-feet high have kept deer out
under some conditions. However, it continues:
Often simple designs are effective only under
light deer pressure (Brenneman,
1983; McAninch
et al., 1983) or for relatively small areas. Low-cost, easily
constructed fences may perform quite well for small areas (less
than ten acres) during the growing season when alternative foods
are available to deer. Low-profile fences, however, are seldom
satisfactory for protecting commercial orchards or ornamental
plantings in winter, especially if snow restricts deer from using
alternative food sources. Landowners must also check local
ordinances and covenants to determine if electric fences can be
used, or if fences of any kind can be constructed on their
property. (DeNicola
et al., 2000)
This 52-page publication discusses many other methods to reduce
deer problems, including repellents, scare tactics, and some
experimental techniques. It includes an excellent 10-page appendix
listing many deer damage control suppliers and materials. The
publication (147IB245) can be ordered for $10.50 postpaid + $5.00
shipping in the U.S. (NY residents add 8.25% sales tax) from:
The Resource Center Cornell University P.O. Box
3884 Ithaca, NY 14852-3884 (607) 255-2080 Fax: (607)
255-9946
The publication is also available at http://legacy.cce.cornell.edu/store/customer/home.php
The enclosed publication Controlling
Deer Damage in Missouri contains information and
illustrations on constructing and using electric, high-tension, and
woven-wire fencing, including the peanut-butter electric fence, the
polytape electric fence, the offset electric fence, the vertical
electric fence, the slanted electric fence, the electric spider
fence, and the wire or plastic mesh fence.
Wireless Deer Fence
A new, patented Wireless Deer Fence consists of just a post less
than 2 feet high, a deer-attractant reservoir, and a battery-powered
high-voltage shocker. It is recommended that 3 to 6 posts be used
for one-third acre, or 15 to 18 per acre. (Williams
and Williams, 2002) For information on price, maintenance, and
installation for the Wireless Deer Fence posts, visit their website
or contact the distributor at:
Wireless
Deer Fence P.O. Box 5604 Bloomington, IN
47407-5604 (866) 468-3337 or (812) 333-5307
Other Exclusion Methods
Another way to exclude deer from small garden areas is to use
floating polyester row covers over the crops to be protected. The
floating row covers need to be put on each evening and removed in
the morning. This method of exclusion was reported to have worked
very well by a gardener in Massachusetts. (Bye,
2000)
Tree protectors or shelters are used to prevent deer from
browsing on young trees. The protectors can be made of polypropylene
tubing, plastic tree wrap, or even woven-wire cylinders.
Polypropylene tubes are commercially available and come in different
diameters for trees or seedlings. Four-or 5-foot shelters are
generally needed in areas of heavy deer pressure. (Pierce
and Wiggers, 1997)
Anecdotal reports suggest that fencing a few pigs in a pen
surrounding the garden will keep deer out. It was reported that the
deer didn't like something about the pigs (smell, size, or sound)
and avoided the garden and pig pen until the pigs were removed.
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Cultural Methods
Deer damage to landscape plants and flowers usually occurs when
the deer's natural browse is low, generally in the late fall through
early spring. By choosing species that are undesirable to deer, you
can reduce the amount of damage to these plants. Plants with a
bitter or spicy taste, milky sap, or thorny, hairy, or tough leaves
and stems are unpalatable to deer. However, the presence of
undesirable plants does not deter deer from feeding on other nearby
plants that they do find palatable. If there is intensive feeding
pressure caused by drought or snow or a high deer density, deer will
browse even the most undesirable plants, and other methods will be
necessary to control damage.
For more information on deer-resistant plants, see the
publications: Controlling
Deer Damage in Missouri, and Resistance
of Ornamentals to Deer Damage (PDF / 1.10MB).
Many other states have publications listing additional deer
resistant plants that are more adaptable to the region. Three of
these sites are Texas' Deer
in the Urban Landscape, Montana's Deer-resistant
Ornamental Plants for Your Garden, and Colorado's Preventing
Deer Damage.
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Scare Devices
Methods for frightening or hazing deer may be effective and
economical in some situations, especially at the first sign of a
problem. Once deer establish a pattern of movement, it is difficult
to get them to change. Propane cannons or gas exploders set to
detonate at irregular intervals are the most common scare devices,
and they are sometimes available for loan from wildlife refuges or
wildlife agencies. Strobe lights and sirens can also be effective;
even fireworks and gunfire can be used as a temporary method.
Playing a radio that goes on and off during the night will work for
a short time, as will attaching a sprinkler system or lights to
motion detectors. The problem with all scare devices is that deer
become accustomed to them within a week or two, even when the
devices are moved occasionally. Varying the scare devices every week
may extend the protection for a longer period. Scare devices are
usually a great short-term solution, but don't depend on them for a
whole growing season.
Dogs
Another scare option is the use of dogs that are kept behind an
"invisible" fence by the use of a radio transmitter, an underground
copper wire, and a special dog collar with receivers. Stationed
inside the invisible fence, the dogs chase the deer out of the dogs'
territory. The collar, when activated by the underground wire, first
gives an audible signal, and if the dogs don't stop they receive a
mild, harmless shock. The dogs must be trained to heed the signals.
Placing the dogs' kennel and water in one area and the food in
another area may help keep the dogs moving around their
territory.
The Cornell publication Managing White-Tailed Deer in
Suburban Environments: A Technical Guide suggests that the
effective area covered by 2 dogs behind invisible fence is about 60
acres or 500 yards from their kennel during the summer. The area is
reduced to about 10 acres during winter, when snow restricts the
movement of the dogs, though snowfall doesn't affect operation of
the electronics. (DeNicola
et al., 2000)
The same publication cautions that care and feeding of the dogs
can be time-consuming and that a family pet may not provide adequate
protection, because it is not patrolling all the time. The authors
explain: "The breed and disposition of the dog will influence
effectiveness of this technique. Large dogs that aggressively patrol
the area appear to work best. The complete protection of plant
materials should not be expected, as deer react to dogs similar to
other scare devices or repellents." (DeNicola
et al., 2000) (Ordering information for this publication is
provided above in the Exclusion
section.)
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Repellents
Repellents are best suited for high-value crops in orchards,
nurseries, and gardens. High cost, limitations on use, and variable
effectiveness make most repellents impractical on row crops,
pasture, or other large areas. There are two kinds of repellents:
contact and area. Contact repellents are applied directly to the
crop plants and repel by taste. Some of these contact repellents use
inedible egg solids to repel deer, while others are derived from
cayenne pepper extract and cannot be applied to the edible portion
of the crop because they will leave a hot taste. Repellents made
from rotten eggs have worked better than several other products in
an Alabama Experiment Station test. (Anon.,
2000) Area repellents are applied near the plants to be
protected and repel deer by smell alone. Some area repellents use
ammonium soaps of fatty acids, bone tar oil, and/or putrefied meat
scraps. Bags of human hair and suspended bars of ordinary hand soap
can also be used as area repellents for deer.
The deer's learning ability causes many repellents to fail over
time. A good way to counter such acclimation is to switch repellents
periodically and to alter their positions near the crop. But as with
planting unpalatable ornamentals, remember that hungry deer
will ignore both taste and odor repellents.
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Culling or Harvest
Culling the animals is another management option. Some states
issue permits to landowners to shoot deer outside the normal sport
hunting season. Only those animals that are damaging crops can be
removed, and such permits are often publicly controversial.
Sport hunting can reduce deer populations and damage over larger
regional areas. To be effective over the long term, does (female
deer) must be removed from the deer population. A "bucks-only" deer
hunt does little to reduce the deer population or the damage done by
overpopulated deer herds. Landowners can reduce the deer population
in their area by soliciting hunters who have "either-sex" deer
permits and who will shoot does. By allowing hunting, landowners can
provide controlled public access to a recreational resource while
reducing deer damage.
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Deer Feeding
A 36-page educational booklet entitled Feeding
Wildlife...Just Say No! is available from the Wildlife
Management Institute. This publication helps explain why
supplemental feeding of big game is costly and rarely beneficial to
wildlife in the short or long run. It helps explain to the public
why wildlife should not be fed, particularly during winter and other
times of stress. (Anon.,
2001) The booklet is available for $3.25 per copy postpaid
from:
WMI Publications P.O. Box 34646 Washington, DC
20043 (202) 371-1808; Fax: (202) 408-5059
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Conclusion
The value of the crop, the amount of deer pressure, and other
variables will affect the suitability and cost effectiveness of
various deer control practices. Check with your state's appropriate
wildlife or natural resource agency on any game regulations that may
restrict your deer management choices.
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References
Anon. 2000. Rotten deer repellents.
Organic Gardening. July–August. p. 15.
Anon. 2001. Wildlife feeding booklet a huge hit.
Outdoor News Bulletin. July 16. p. 4.
Associated Press. 2000. Deer population posing
problems. Environmental News Network Web site.http://www.enn.com/news/.
October 15. 2 p.
Brennemen, R.
1983. Use of electric fencing to prevent deer browsing in Allegheny
hardwood forests. Eastern Wildlife Damage Control Conference. Vol.
1. p. 97–98.
Bye, Muriel. 2000.
Easy,effective deer control. Organic Gardening. May–June. p.
66.
Caslick, J. W., and D. J.
Decker. 1979. Economic feasibility of a deer-proof fence for apple
orchards. Wildlife Society Bulletin. Vol. 7. p. 173–175.
DeNicola, Anthony J., Kurt C. VerCauteren,
Paul D. Curtis, and Scott E. Hygnstrom. 2000. Managing White-Tailed
Deer in Suburban Environments: A Technical Guide. Cornell
University. 147IB245. 52 p.
McAninch, J. B., M. R. Ellingwood, and R. J.
Winchcombe. 1983. Deer damage control in New York agriculture. New
York State Department of Agriculture and Markets, Division of Plant
Industry, Albany, N.Y.
Mullen,
Matt. 2002. Oh, deer. Farmer's Digest. June–July. p.
84–87.
Pierce II, Robert A., and
Ernie P. Wiggers. 1997. Controlling deer damage in Missouri.
University of Missouri–Columbia. MP685. November 1. 21 p. http://muextension.missouri.edu/xplor/miscpubs/mp0685.htm.
Williams, Greg, and Pat Williams. 2002.
Fenceless deer fencing? HortIdeas. March. p. 32.
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Enclosures
Kays, Jonathan S., Lisa Curtis, and Michael V. Bartlett. No date.
Resistance of ornamentals to deer damage. Maryland Cooperative
Extension. Fact Sheet 655. 8 p. www.agnr.umd.edu/MCE/publications/PDFs/FS655.pdf.
(PDF / 1.10MB)
Pierce II, Robert A., and Ernie P. Wiggers.
1997. Controlling deer damage in Missouri. University of
Missouri–Columbia. MP685. 21 p. http://muextension.missouri.edu/xplor/miscpubs/mp0685.htm.
Deer Control Options By Lance E.
Gegner NCAT Agriculture Specialist Paul Williams,
Editor Cole Loeffler, HTML Production CT 131 Slot 105
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