Animal Pests

Four-footed creatures can cause much more damage than insect pests in many suburban and rural gardens. They may ruin your garden or landscape overnight, eating anything from apples to zinnias. Most animal pests feed at night, making it tricky to figure out who the culprits are.

Follow these guidelines for coping with animal pests.

Identify the pests. Ask your neighbors what kinds of wildlife are common garden marauders in your neighborhood. Sit quietly looking out a window toward your garden at dawn or dusk, when animals tend to become active. Check for droppings or paw prints around your garden, and consult a wildlife guide to identify them.

Assess the damage. If it’s only cosmetic, you may decide your plants can tolerate it. If the damage threatens harvest or plant health, control is necessary. If damage to ornamental plants is limited to one plant type, consider digging it out and replacing it with plants that are less appealing to animal pests.

Take action. Combining several tactics to deter animal pests may be most effective. For a vegetable or kitchen garden, a sturdy fence is often the only effective choice. Barriers work well to protect individual plants. Homemade or commercial repellents give inconsistent results, so use them experimentally. Scare tactics such as scarecrows and models of predator animals may frighten pest animals and birds. In extreme cases, you may choose to kill the pests by flooding their underground tunnels or by trapping or shooting. It’s up to the individual to decide if the damage is severe enough to warrant these methods. If you decide to shoot or trap any animals, check first with your state Department of Environmental Resources to learn about regulations and required permits.

Deer

Deer have a taste for a wide range of garden and landscape plants. A few deer are a gentle nuisance; in areas with high deer pressure, they can be the worst garden pest you’ll ever encounter. Deer are nocturnal, but may be active at any time. In areas where they’ve acclimated to humans, you may spot them browsing in your garden even in the middle of the afternoon.

Barriers: If deer are damaging a few select trees or shrubs, encircle the plants with 4-foot-high cages made from galvanized hardware cloth, positioned several feet away from the plants.

Fences: Fencing is the most reliable way to keep deer out of a large garden or an entire home landscape, but some types are quite costly, especially if you have it installed by a professional. Here are your options for deer fencing:

 Conventional wire-mesh fences should be 8 feet high for best protection. A second, inner fence about 3 feet high will increase effectiveness because double obstacles confuse deer.

 Slanted fences constructed with electrified wire are an excellent deer barrier. Installing this type of fence is a job for a professional.

 Deer are not likely to jump a high, solid fence, such as one made of stone or wood.

 Polypropylene (plastic) mesh deer fencing is costly, but easier to install on your own than an electric fence.

 For small gardens, up to 40 feet by 60 feet, a shorter enclosure made of snow fencing or woven-wire fencing may be effective, because deer don’t like to jump into a confined space.

 

Repellents: For minor deer-damage problems, repellents will be effective for awhile, but eventually the deer will probably grow accustomed to the repellent and begin browsing again. Under the pressure of a scarce food supply, deer may even learn to use the odor of repellents as guides to choice food sources. Periodically changing from one type of repellent to another can increase your chances for success. You can make your own or buy a commercial repellent.

 Hang bars of highly fragrant soap from strings in trees and shrubs. Or nail each bar to a 4-foot stake and drive the stakes at 15-foot intervals along the perimeter of the area.

 Try using human hair. Ask your hairdresser to save hair for you to collect each week. Put a handful of hair in a net or mesh bag (you can use squares of cheesecloth to make bags), and hang bags 3 feet above the ground and 3 feet apart.

 Farmers and foresters repel deer by spraying trees or crops with an egg-water mixture. Mix 5 eggs with 5 quarts of water for enough solution to treat ¼ acre. Spray plants thoroughly. You may need to repeat application after a rain.

 Commercial repellents are available at garden centers. Be sure to ask if a product contains only organic ingredients. You may have to experiment to find one that offers good control. Watch for new products coming on the market, too. For example, preliminary tests of milk powder as a deer repellent seem promising.

 Experiment with homemade repellents by mixing blood meal, bonemeal, exotic animal manure, hot sauce, or garlic oil with water. Recipes for concocting these repellents differ, and results are variable. Saturate rags or string with the mixtures, and place them around areas that need protection.

 Some gardeners who own male dogs that regularly patrol their yards report that they have few deer problems, even though they don’t have a fence or use repellents. It seems that the scent of the dogs is enough to discourage deer from spending much time in the area.

Deer-proof plants: If fencing your yard is beyond your budget, and repellents aren’t doing the trick, you could try revamping your landscape with plants that deer don’t like to eat. Over time, remove the plants that deer have damaged so badly that they’ve lost their attractiveness 37or never flower. Replace them with shrubs, vines, and perennials with a reputation for being deer-proof. There’s no hard-and-fast list, and it’s possible that the deer in one region may dislike plants that are quite palatable to deer in another. Ask your Cooperative Extension service for a list of plants that seem to be locally deer-proof, and consult the Resources section for books on the topic.

 

Ground Squirrels and Chipmunks

Ground squirrels and chipmunks are burrowing rodents that eat seeds, nuts, fruits, roots, bulbs, and other foods. They are similar, and both are closely related to squirrels. They tunnel in soil and uproot newly planted bulbs, plants, and seeds. Ground squirrel burrows run horizontally; chipmunk burrows run almost vertically.

Traps: Bait live traps with peanut butter, oats, or nut meats. Check traps daily.

Habitat modification: Ground squirrels and chipmunks prefer to scout for enemies from the protection of their burrow entrance. Try establishing a tall groundcover to block the view at ground level.

Other methods: Place screen or hardware cloth over plants, or insert it in the soil around bulbs and seeds. Try spraying repellents on bulbs and seeds.

Mice and Voles

Mice and voles look alike and cause similar damage, but they are only distantly related. They are active at all times of day, year-round. They eat almost any green vegetation, including tubers and bulbs. When unable to find other foods, mice and voles will eat the bark and roots of fruit trees. They can do severe damage to young apple trees.

Barriers: Sink cylinders of hardware cloth, heavy plastic, or sheet metal several inches into the soil around the bases of trees. You may be able to protect bulbs and vegetable beds by mixing a product containing slate particles into the soil.

Traps and baits: Some orchardists place snap traps baited with peanut butter, nut meats, or rolled oats along mouse runways to catch and kill them. A bait of vitamin D is available. It causes a calcium imbalance in the animals, and they will die several days after eating the bait.

Other methods: Repellents such as those described for deer may control damage. You can also modify habitat to discourage mice and voles by removing vegetative cover around tree and shrub trunks.

Moles

In some ways, moles are a gardener’s allies. They aerate soil and eat insects, including many plant pests. However, they also eat earthworms. Their tunnels can be an annoyance in gardens and under your lawn. Mice and other small animals also may use the tunnels and eat the plants that moles have left behind.

Traps: Harpoon traps placed along main runs will kill the moles as they travel through their tunnels.

Barriers: To prevent moles from invading an area, dig a trench about 6 inches wide and 2 feet deep. Fill it with stones or dried, compact material such as crushed shells. Cover the material with a thin layer of soil.

Habitat modification: In lawns, insects such as soil-dwelling Japanese beetle grubs may be the moles’ main food source. If you’re patient, you can solve your mole (and your grub) problem by applying milky disease spores, a biological control agent, to your lawn. This is more effective in the South than in the North, because the disease may not overwinter well in cold conditions. However, if you have a healthy organic soil, the moles may still feed on earthworms once the grubs are gone.

Other methods: You can flood mole tunnels and kill the moles with a shovel as they come to the surface to escape the water. Repellents such as those used to control deer may be effective. Unfortunately, repellents often merely divert the moles to an area that is unprotected by repellents.

 

Pocket Gophers

These thick-bodied rodents tunnel through soil, eating bulbs, tubers, roots, seeds, and woody plants. Fan- or crescent-shaped mounds of soil at tunnel entrances are signs of pocket gopher activity.

Fences and barriers: Exclude gophers from your yard with an underground fence. Bury a strip of hardware cloth so that it extends 2 feet below and 2 feet above the soil surface around your garden or around individual trees. A border of oleander plants may repel gophers.

Flooding: You can kill pocket gophers as you would moles, by flooding them out of their tunnels.

Rabbits

Rabbits can damage vegetables, flowers, and trees at any time of year in any setting. They also eat spring tulip shoots, tree bark, and buds and stems of woody plants.

Look, Don’t Touch

While we may wish that solving animal pest problems were as easy as posting a “Look, Don’t Touch” sign, we should heed the warning ourselves when dealing with animal pests. Wild animals are unpredictable, so keep your distance. They may bite or scratch and, in doing so, can transmit serious diseases such as rabies. Any warm-blooded animal can carry rabies, a virus that affects the nervous system. Rabies is a threat in varying degrees throughout the United States and Canada. Among common garden animal pests, raccoons and skunks are most likely to be infected. It’s best never to try to move close to or touch wild animals in your garden. And if you’re planning to catch animal pests in live traps, be sure you’ve planned a safe way to transport and release the animals before you set out the baited traps.

Fences: The best way to keep rabbits out of a garden is to erect a chicken-wire fence. Be sure the mesh is 1 inch or smaller so that young rabbits can’t get through. You’ll find instructions for constructing a chicken-wire fence in the Fencing entry.

Barriers: Erect cylinders made of ¼-inch hardware cloth around young trees or valuable plants. The cages should be 1½ to 2 feet high, or higher if you live in an area with deep snowfall, and should be sunk 2 to 3 inches below the soil surface. Position them 1 to 2 inches away from the tree trunks. Commercial tree guards are also available.

Other methods: Repellents such as those used for deer may be effective. Commercial inflatable snakes may scare rabbits from your garden.

Raccoons

Raccoons prefer a meal of fresh crayfish but will settle for a nighttime feast in your sweet corn patch. Signs that they have dined include broken stalks, shredded husks, scattered kernels, and gnawed cob ends.

Fences and habitat modification: A fence made of electrified netting attached to fiberglass posts will keep out raccoons, rabbits, and woodchucks. Or if you have a conventional fence, add a single strand of electric wire or polytape around the outside to prevent raccoons from climbing the fence. Try lighting the garden at night or planting squash among the corn—the prickly foliage may be enough to deter the raccoons.

Barriers: Protect small plantings by wrapping ears at top and bottom with strong tape. Loop the tape around the tip, then around the stalk, then around the base of each ear. This prevents raccoons from pulling the ears off the plants. Or try covering each ear with a paper bag secured with a rubber band.

 

Woodchucks

Woodchucks, or groundhogs, are found in the Northeast, the Mid-Atlantic, parts of the Midwest, and most of southern Canada. You are most likely to see woodchucks in the early morning or late afternoon, munching on a variety of green vegetation. Woodchucks hibernate during winter. They’re most likely to be a pest in early spring, eating young plants in your gardens.

Fences: A sturdy chicken-wire fence with a chicken-wire-lined trench will keep out woodchucks.

Barriers: Some gardeners protect their young plants from woodchucks by covering them with plastic or floating row covers.

Other Animal Pests

The following animals cause only minor damage to gardens or are pests only in a limited area of the country.

Armadillos: These animals spend most of the day in burrows, coming out at dusk to begin the night’s work of digging for food and building burrows. Their diet includes insects, worms, slugs, crayfish, carrion, and eggs. They will sometimes root for food in gardens or lawns. Armadillos cannot tolerate cold weather, which limits their range to the southern United States.

A garden fence is the best protection against armadillos. You also can trap them.

Prairie dogs: Prairie dogs can be garden pests in the western United States. They will eat most green plants. If they are a problem in your landscape, control them with the same tactics described for ground squirrels and pocket gophers.

Skunks: Skunks eat a wide range of foods. They will dig holes in your lawn while foraging and may eat garden plants. Skunks can be a real problem when challenged by pets or unwary gardeners.

Keep skunks out of the garden by fencing it. You can try treating your lawn with milky disease spores to kill grubs.

Squirrels: Squirrels eat forest seeds, berries, bark, buds, flowers, and fungi. Around homes, they may feed on grain, especially field corn. Damage is usually not serious enough to cause concern. Try using repellents such as those suggested for deer control to protect small areas.

 

Bird Pests

To the gardener, birds are both friends and foes. While they eat insect pests, many birds also consume entire fruits or vegetables or will pick at your produce, leaving damage that invites disease and spoils your harvest.

Some of the birds likely to raid your vegetable gardens are blue jays and blackbirds such as crows, starlings, and grackles. If you grow berries or tree fruit, you may find yourself playing host to beautiful but hungry songbirds such as cedar waxwings and orioles. You’ll have to decide which you enjoy more—eating the fruit or birdwatching!

Scare Tactics

Many gardeners report success in using commercial or homemade devices to frighten birds away from their crops.

Fake enemies: You can scare birds by fooling them into thinking their enemies are present. Try placing inflatable, solid, or silhouetted likenesses of snakes, hawks, or owls strategically around your garden to discourage both birds and small mammals. They’ll be most effective if you occasionally reposition them so that they appear to move about the garden. Hang “scare-eye” and hawklike balloons and kites that mimic bird predators in large plantings. Use 4 to 8 balloons per acre in orchards or small fruit or sweet corn plantings.

Weird noises: Unusual noises can also frighten birds. A humming line works well in a strawberry patch or vegetable garden. The line, made of very thin nylon, vibrates in even the slightest breeze. The movement creates humming noises inaudible to us, but readily heard and avoided by birds. Leaving a radio on at night in the garden can scare away some pests. A word to the wise: Commercially available ultrasonic devices that purport to scare animal and bird pests are unreliable.

Flashes of light: Try fastening aluminum pie plates or unwanted CDs to stakes with strings in and around your garden. Blinking lights may work, too.

Sticky surfaces: Another tactic that may annoy or scare birds is to coat surfaces near the garden where they might roost with Bird Tanglefoot.

And don’t forget two tried-and-true methods: making a scarecrow and keeping a domestic dog on your property.

In general, birds feed most heavily in the morning and again in late afternoon. Schedule your control tactics to coincide with feeding times. Many birds have a decided preference for certain crops. Damage may be seasonal, depending on harvest time of their favorite foods.

You can control bird damage through habitat management or by blocking their access or scaring them away from your garden (see “Scare Tactics”). For any method, it is important to identify the bird. A control effective for one species may not work for another. Also, you don’t want to mistakenly scare or repel beneficial birds.

Try these steps to change the garden environment to discourage pesky birds:

•  Eliminate standing water. Birds need a source of drinking water, and a source near your garden makes it more attractive.
•  Plant alternate food sources to distract birds from your crop.
•  In orchards, prune to open the canopy, since birds prefer sheltered areas.
•  In orchards, allow a cover crop to grow about 9 inches tall. The growth will be too high for birds who watch for enemies on the ground while foraging.
•  Remove garden trash and cover possible perches to discourage smaller flocking birds like sparrows and finches that often post a guard.

You can also take steps to prevent birds from reaching your crops. The most effective way is to cover bushes and trees with lightweight plastic netting, and to cover crop rows with floating row covers.