GOPHERS AT A GLANCE
Dig long, deep tunnels beneath lawns and gardens
Love roots and tubers, but eat all kinds of plant material, in large quantities
To control them, stuff ammonia-soaked rags, used cat litter, or other strong-smelling substances into tunnels
Spray their target areas with Gopher-Go Tonic (Below)
Deter by planting caper spurge (Euphorbia lathyrus)
Female gophers give birth to 1 to 10 babies per litter, but the average is 3 to 4. Within about six weeks, Mom kicks them out to fend for themselves. About a year later, they reach maturity and start their own families. In cold climates, gophers produce just one litter per year, generally between March and June; but in balmy places, breeding can go on year-round.
Gophers are gluttons, pure and simple. Root vegetables rank near the top of their most-wanted list, but they also go gaga for tomatoes, peppers, squash, melons, cucumbers, and (are you ready for this?) garlic, which most pests won't touch. And they just love to munch on tulips, lilies, dahlias, hollyhocks, and the roots of fruit trees and grape vines.
Evidence of gophers is sometimes mistaken for that of moles, because the two little critters share the same simple approach to life: Dig it, man! Both of these terrific tunnelers spend their lives underground, never venturing to the surface if they can help it. But there, the similarities end. Moles eat only grubs and other insects; any damage they do to plants is a byproduct of their enthusiasm for the chase Gophers, on the other hand, are rodents who eat nothing but plants, and plenty of them. They're not subtle about it, either. When one of these guys is at work, you'll see no telltale signs of below-ground nibbling, such as limp stems or yellowing foliage. Instead, a plant that's growing great guns one minute will keel over onto its side the next-or even be pulled into the ground, lock, stock, and leaf tips!
Biology, Reproduction and Behavior
Pocket gophers feed on roots they encounter from digging, from vegetation they pull into the tunnel from below, and vegetation above ground near the tunnel. They like above-ground vegetation when it is green and succulent. Pocket gophers prefer alfalfa. Many trees and shrubs are clipped just above ground, especially under snow cover.
Pocket gophers construct burrow systems by loosening the soil with their claws and incisors, then use their forefeet and chest to push the soil out of the burrow. The soil is deposited in fan-shaped mounds 12 to 18 inches wide and 4 to 6 inches high.
Figure 2: Pocket gopher mound and its relation to the tunnel system.
Burrow systems consist of a main tunnel, generally 4 to 18 inches below the soil surface, and a variable number of lateral burrows extending from the main. Lateral burrows end with a soil mound or only a soil plug at the surface. Burrows are about 2 to 3 1/2 inches in diameter, depending on the size of the gopher. A burrow system may be linear to highly branched, may contain up to 200 yards of tunnels, and may have a hundred or more mounds.
Pocket gophers usually construct one to three mounds per day although the rate varies. One gopher brings about 2 1/4 tons of soil to the surface each year. Mound-building activity usually is greatest in spring and fall.
Pocket gophers usually breed in the spring and produce one litter of one to 10 young (typically three to four) after a gestation period of about 20 days. Usually, only one adult is found in each burrow system except during breeding and while raising young. Six to eight plains pocket gophers per acre are considered high densities whereas northern pocket gophers occasionally reach densities of 20 per acre. Young pocket gophers usually begin dispersing from the natal burrow in June when about one-third grown.
Pocket gophers are consumed by owls, hawks, badgers, coyotes, foxes, bobcats, skunks, weasels, bullsnakes and rattlesnakes.
Heading for the Green
There are 33 different species of gophers in the U.S. They range in length from 6 to 12 inches, and in weight from 8 ounces to a full pound. They have external pouches on their cheeks, where they store their booty as they travel along-and travel they do, far and deep, in their quest for food and warm, cozy lodgings. In fact, a lone gopher can tunnel as far as 300 feet in a single night. Gophers have long, sharp claws to dig with, sensitive whiskers that help them navigate through their dark tunnels, and lips that close behind their incisor teeth-so that no soil goes into their tummies along with those tasty roots, shoots, and tubers.
Gophers perambulate throughout the country, but they tend to cause the most trouble in the stretch from Indiana west to the Pacific Ocean.
Damage and Control
Pocket gophers reduce the productivity of alfalfa fields and native grasslands on which they are found by 20 to 50 percent. If gophers are present on 10 percent of a field, they may reduce overall forage productivity of the field by 2 to 5 percent. Gopher mounds dull and plug sickle bars when harvesting hay or alfalfa. Gophers sometimes damage trees by girdling or clipping stems and by pruning roots. Gophers may, at times, destroy underground utility cables and irrigation pipes.
In retrospect, gophers are beneficial in several ways. Their burrowing activities increase soil fertility by adding organic matter in the form of plant materials and feces. Their burrowing increases soil aeration, increases water infiltration, reduces compaction, and increases the rate of soil formation by bringing up subsoil subjecting it to weatherization.
Gophers are not protected by state or federal laws. When selecting a damage-control program, consider nonlethal measures such as habitat modification or appropriate alfalfa varieties, which may be as cost effective as lethal measures and should minimize adverse environmental impacts. It is important to maintain biodiversity, or to retain the existing plants and animals that may later benefit humans and assist in maintaining ecosystem function.
Because defending your territory from gophers is no easy task, before you do anything, make sure it's gophers who've come a-callin', and not moles or ground squirrels. You can tell by simply eyeballing the tunnel entrances. At a gopher's front door, you'll see a U- or crescent-shaped mound of moist soil that looks as though it's been sifted. Moles make round mounds at their entrance holes, and ground squirrels leave no kicked-up soil at all.
Once you've got a positive I.D., act fast, because a single tunnel can turn into a maze the size of the New York subway system faster than you can say, "Take the A-Train." Before you even start contemplating longer-term measures, soak some sponges or old T-shirts in ammonia, and stuff one into each hole. Then seal them all up. Those G-men will dig out in a hurry! Next, mix up a batch of Gopher-Go Tonic (below) and dribble it around your garden. That way, when the little varmints pop up out of their tunnels, they'll quickly take off for less aromatic quarters.
No ammonia on hand? Don't worry. Plenty of other scents make gophers pack up and head outta town (or at least out of your yard). Whichever one you use, there are two keys to success: Wear gloves so you don't transfer your scent to the repellent, and seal all the entrance holes you can find, so the tunnel gets good and smelly. Here are some of the best, easy-to-come-by odor emitters:
1 Juicy Fruit gum
1 Rotting garbage
1 Used cat litter
1 Paper towels soaked in rancid oil
1 Dog or cat hair
One of the most effective gopher chasers is as close as the trunk of your car-or the nearest auto parts store. What is it? A highway emergency flare! Just cut through the "candle" with a sharp knife (not a saw), then dig into the tunnel, and sprinkle the contents (powdered sulfur) inside. Close up the entrance, as well as any exit holes that you've been able to find. The more airtight the tunnel system is, the more eager the gophers will be to vacate the premises. Keep up your efforts until new mounds no longer appear. Then you'll know the nogoodniks have gone for good!
To fence or Not to fence
If your yard has more gophers than Georgia has peaches, you might be tempted to surround the whole plot with a mostly underground fence. Will it keep the rascals out? It might, in some parts of the country, but don't bet the family farm on it! Gopher tunnels have been reported as deep as 6'/2 feet, and there's no telling how far down the little diggers can go if they set their minds to it.
If you decide to go with a fence, use wire mesh with openings that are no bigger than 1/4 inch across. Leave 6 to 12 inches above ground (gophers rarely strike from the surface), and extend the barrier as far below as your will to dig and budget allow; but I'd recommend no less than 2 1/2 feet.
Pocket gophers can be excluded from valuable plots of ornamental trees and shrubs with a 1/4 to 1/2-inch mesh hardware cloth fence buried at least 18 inches. The bottom of the fence should be bent at a 90-degree angle so that a 6-inch apron of wire projects horizontally toward the gopher. Place the fence in shallow soil at least 2 feet from the nearest plants to avoid root injury. This method is of limited practicality because of expense and labor. Cylindrical plastic Vexar mesh tubes placed over the entire seedling, including bare root, can reduce damage to newly planted seedlings.
The most effective (and affordable) anti-gopher "fence" is 1/2-inch galvanized wire mesh lining the bottom and sides of each planting hole, or the entire bed if it's small enough. Lay the screen about 2 feet under the surface, and make sure it covers the sides all the way up to a few inches above the soil surface. Don't leave any gaps, because these little contortionists can squeeze through even the teeniest openings.
Figure 3: Trap placement in burrow systems: (A) Place two traps set in opposite directions in main tunnel; (B) set single trap in lateral tunnel from which soil plug has been removed. Wire each trap to a stake.
Traps also can be set in the main tunnel located about 12 to 18 inches from the mound. After uncovering the main tunnel with a shovel, set two traps as shown in Figure 3. The tunnels either can be left open or covered after setting traps. Check traps twice daily since gophers often visit the traps within a few hours. If a trap is not visited within 48 hours, move it to a new location. Trapping usually is most successful in the spring and fall when gophers are actively building mounds.
Splurge on Spurge
When gophers are gobbling up your garden, buy as much caper spurge (Euphorbia lathyrus) as you can afford. Then plant it all around the perimeter of your garden. The roots produce an acrid, milky juice that gophers can't stand. One whiff, and they'll find another dining establishment!
Like a lot of critters, gophers are very sensitive to sound
vibrations. To use that fact to your advantage, just gather up six or eight
empty glass bottles and half-bury them, top ends up, in a line near the gophers'
hangouts. When the wind passes over them, it'll let out a scary noise that'll
make the little guys scurry in a hurry.
Back in Grandma’s day, folks sent gophers packin' by putting fish heads in their burrows. The little guys couldn't stand the smell, so they got outta Dodge fast. If you try this trick, just be aware that although you will get rid of the gophers, you just might wind up entertaining a different crowd of equally unwelcome critters who are attracted to the stench.
Four rodenticides are
registered for pocket gopher control:
· strychnine (0.25 to 0.5 percent active ingredient),
· zinc phosphide (2 percent active ingredient),
· chlorophacinone (Rozol) (0.005 percent active ingredient), and
· diphacinone (Eaton's Answer)(0.005 percent active ingredient).
Strychnine, formulated on milo, barley or wheat, is a widely used toxicant but is highly toxic and potentially hazardous to all wildlife. It usually is labeled as a Restricted-Use Pesticide. Underground baiting with strychnine presents minimal hazards to non-target wildlife but any grain spilled on the surface may be hazardous to ground-feeding birds.
In some studies, zinc phosphide has been less effective than strychnine. Diphacinone (Eaton's Answer) is blended with a water resistant material and is formulated in bait blocks. The blocks provide long-term control because the bait remains effective after killing resident gophers so that invading gophers also are eliminated. Since chlorophacinone (Rozol) is a multiple dose anticoagulant, more bait is required to achieve adequate control. To poison pocket gophers, place the bait in their tunnel systems by hand or with a burrow builder machine.
Place bait into a burrow system by hand after opening the main tunnel or with a hand probe. Treat two or three of the freshest mounds within each burrow system (a circle with about a 100-foot diameter). To place bait in the burrow system by hand, locate the main tunnel by digging with a shovel 12 to 18 inches from the plug side of the mound. Place the recommended amount of bait, following label directions, in each direction of the opened main tunnel and well into the system. Close off each tunnel with sod clumps and soil so gophers do not attempt to close the system and cover the bait with soil.
Figure 4: Gopher bait application. (A) Hand application: remove plug in tunnel, starting from gopher mound. Place quantity of bait into main tunnel with a long-handled spoon. Seal tunnel with sod, do not cover bait with soil. (B) Probe application: Locate main tunnel with probe as described in text. With spoon, drop bait into tunnel through hole made by probe. Cover probe hole with sod. Bait-dispensing probe: Locate main tunnel with probe, push lever or plunger to dispense bait into tunnel, cover probe hole with sod.
A less time-consuming baiting method involves using a pointed-rod hand probe. Locate the main tunnel 12 to 18 inches from the plug side of the mound by pressing the probe into the ground (Figure 4). Determine the location of the tunnel by the decreased friction on the probe. Place bait through the probe hole into the tunnel. A reservoir-type bait probe dispenser also is available for poisoning gophers (Figure 4). A button is pushed on the bait probe when it is pushed in the burrow and a metered dose of bait drops into the burrow. Place the recommended amount of bait down each of two or three probe openings and then cover the probe holes with sod.
The burrow builder mechanically delivers bait underground so large acreages can be economically treated for pocket gopher control. Burrow builders are available in a standard hydraulically operated unit or a three-point hitch model. The device consists of a knife and torpedo assembly that makes an artificial burrow at desired soil depths, a coulter blade that cuts roots of plants ahead of the knife, a seeder assembly for bait dispensing, and packer wheel assembly to close the furrow behind the knife. The seeder box has a metering device for dispensing various poison baits at desired rates. Burrow builders can be used successfully in agricultural mountainous areas if the soil is not extremely rocky. However, operations on steep slopes can result in poorly constructed tunnels or damage to the torpedo.
To achieve good results with a burrow builder:
1. Adjust the burrow builder to construct tunnels at the same depth as those constructed by gophers in your area so gophers intercept the tunnels.
2. Use the machine only when the soil moisture is adequate because if the soil is too dry the burrow may collapse and if the soil is too wet the slot over the tunnel may not close (generally, the soil moisture is adequate if a compressed handful holds its shape).
3. Space the burrows at 20- to 30-foot intervals in areas of infestation (burrow spacing is dependent on gopher densities and species involved; usual spacing for the northern and Botta's pocket gophers is 20 to 25 feet and 25 to 30 feet for the plains and yellow-faced pocket gophers).
4. Periodically check to assure formation of a good burrow and check if bait is dispensing down the tube.
5. Enclose the perimeter of the field with artificial burrows to prevent reinvasion.
6. Follow directions provided with the burrow builder machine.
Recommended application rates of 1 to 2 pounds per acre of 0.35 to 0.5 percent strychnine provide 85 to 95 percent control. Clean up any spilled bait and properly dispose. Bury any dead gophers found above ground to reduce hazards to predators and scavengers. Harrowing the field about one week after treatment to level mounds and then retreating by hand or trapping at new mounds should result in more complete control.
Fumigants, such as aluminum phosphide and gas cartridges, are not very successful for controlling pocket gophers because gophers either sense the poisonous gas and plug the tunnel or the fumigants diffuse into the soil, particularly when it is dry. Pocket gophers reportedly can be controlled by injecting exhaust from an old vehicle without antipollution devices into the burrow for about 3 minutes.
When gophers just won't give up, reach for this remarkable recipe.
4 tbsp. of castor oil
4 tbsp. of dishwashing liquid
4 tbsp. of urine
1/2 cup of warm water
2 gal. of warm water
Combine the oil, dishwashing liquid, and urine in 1/2 cup of warm water, then stir the solution into 2 gallons of warm water. Pour the mixture over any problem areas, and the gophers will gallop away!