[Vertebrate Pests] Managing Pocket Gophers

ocket gophers are medium-size burrowing rodents that spend 99 percent of their lives living in underground tunnels and nests. Pocket gophers have external fur-lined cheek pouches located on the outside of their mouths. The pouches are used to store food that is carried back to their nests.

There are 35 species of pocket gophers in the Americas. This mammal is powerfully built in the forequarters and has a short neck. They are powerful diggers and have front paws with large claws. The external ears and eyes are quite small. The incisors are perhaps the largest in relation to body size of all mammals. The pocket gopher is adept at digging.

HABITAT. Pocket gophers occupy a variety of habitats, which range in elevation from above 12,000 feet to sea level. Soil type, texture and moisture determine whether or not gophers will occupy a given area. The tunnels excavated by the mammal range from ½ to 1 foot below the surface. Deeper tunnels, as deep as 6 feet, are common with most species. The sub-surface tunnels are used mostly for feeding and the deeper ones are used to escape extremes in climate, build nests and raise litters.

Pocket gophers eat the roots of grasses, forbs, shrubs and even small trees and can be destructive in forest plantations. (Each year the U.S. Forest Service contracts with pest management firms to control pocket gopher to protect newly planted tree seedlings.) Pocket gophers are herbivores and cause havoc in yards as they damage lawns, gardens and flowerbeds. The burrow system is multi-branched and individuals tend to be territorial. In studies in California with radio collars on gophers, some animals were observed to move 200 to 300 feet per night. A single pocket gopher may construct as many as 300 soil mounds in a year while moving more than 4 tons of soil within a few weeks of work. Burrows are continually changing, with old tunnels being sealed off and new ones excavated. No one really knows how many linear feet of tunnels a single pocket gopher can construct in a lifetime, but it is undoubtedly thousands of feet.

Pocket gophers are active all year, even when snow is present. Typically, the mammal cruises along its tunnel system and nips the roots of plants growing above the tunnel found dangling within the corridors. An easy method to determine if a pocket gopher occupies a tunnel system is to simply dig open the tunnel. If a gopher lives in the tunnel, the hole will be plugged within a day or two.

POCKET GOPHERS VS. MOLES. Pest management professionals sometimes have difficulty in differentiating between pocket gopher and mole damage to lawns or turf. Moles construct more vertical mounds and pocket gopher diggings tend to be more fan-shaped. Voles have shallow tunnels and leave the burrows open, having a diameter of only 1 to 1½ inches. Both moles and pocket gophers plug their tunnels with dirt to ensure a constant environment within the system.

Pocket gophers are difficult to control. Traps, EPA-approved baits and exclusion are the most often used techniques to reduce damage. Baits may include active ingredients such as strychnine, diphacinone, chlorophacinone and zinc phosphide. Fumigants in the form of tablets or ignited cartridges can be used to control pocket gophers. But because of the length of the tunnel systems, such fumigants may not be very effective. (See additional control techniques at left.)

It may be difficult to differentiate between pocket gopher and mole damage. If you have questions, send a photo to me at rpoche@giemedia.com and I’d be happy to help you identify the type of damage.

The author is founder of Scimetrics, a rodent product manufacturer in Wellington, Colo.

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POCKET GOPHERS ID TIPS

• Pocket gophers are 5 to 14 inches long (adult body length)

• They weigh 3 to 20 ounces (adult body weight)

• Their gestation period is 18 to 51 days

• Pocket gophers are active during the morning and late afternoon into evening

• They have one litter per year in the North, two per year in the South

Source: Mallis Handbook of Pest Control

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POCKET GOPHER CONTROL FROM SCIMETRICS

Baits can be applied directly into pocket gophers tunnel system by use of a hand probe, control bait release probe, or artificial burrow builder. Scimetrics, a product manufacturer based in Wellington, Colo., offers the Sub-Station, a patent-pending underground bait station. Bait is dispensed into the station via a tube that extends above ground and has a cap on the end. Gophers enter the station and generally empty the bait within a day or two. It is transported to the nest and the station is left empty. Sometimes the mammal will fill the station with soil after the bait is removed. Simply clean out the station and provide more bait until the gopher is eliminated.

With Kaput-D, simply probe a hole to intersect the pocket gopher tunnel. Then, slowly pour ½ cup of bait into the tunnel and close the hole carefully. The pocket gophers should be eliminated within a week, Scimetrics reports.

Visit www.scimetricsltd.com for additional information.