   Pocket Gophers - December 16, 1998 Jeff Schalau, County Director, Agent, Agriculture & Natural Resources Arizona Cooperative Extension, Yavapai County Pocket gophers are probably the most common vertebrate garden pest encountered by Arizona gardeners. To effectively control them, one must learn their habits and become a dedicated observer. This article will cover identification, behavior, breeding, and control measures of pocket gophers. Of the three species of pocket gophers found in Arizona, the Valley Pocket Gopher is most common. To be sure you are dealing with a pocket gopher, look for a round mound of loose soil that has a smaller plug of loose soil in the center or to one side within the main mound. If you don't see this characteristic mound, then you may have another pest such as a rock squirrel. Pocket gophers live their entire lives in the soil, leaving only to occasionally feed above ground, to travel to a new area, or to get around an obstacle. They usually are five to seven inches long (without the tail), have pale to dark brown fur, wide headed, have enlarged front feet (the better dig with), have long upper and lower front teeth (the better to eat roots with), and a short tail with tactile hairs to allow them to feel their way when traveling in reverse. Pocket gophers are named for their fur-lined pouches outside of the mouth, one on each side of the face. These pockets are capable of being turned inside out and used for carrying food and moving soil. Pocket gophers have one or two litters per year. These consist of between one and ten (usually three or four) offspring per litter. Their burrows are between 4-18 inched deep, may be linear or branched, and usually have deeper side branches that serve as nests or food caches. The previously described characteristic mounds are at the ends of tunnel branches and each gopher can push up one to three mounds per day. The mounds give an indication of areas with the greatest feeding or nesting activity. Feeding occurs in three ways: 1) feeding on roots they encounter while digging; 2) surface feeding a body length or so from their tunnel opening; and 3) pulling vegetation into the tunnel from below. These strict vegetarians may feed on herbs, grasses, bulbs, shrubs, and trees. Alfalfa and dandelions are preferred foods, although other tap-rooted weeds can attract gophers. Pocket gophers may be controlled with varying success by trapping, gassing, poisoning, flooding, cultural methods, use of repellents, and exclusion. As harsh as it may seem, I always recommend using lethal traps such as the Macabee wire trap. Buy at least two traps and use two feet of wire to tie them to a common stake. Traps should be set in pairs. Using a probe to find a main tunnel, excavate the area, set each trap and insert it well into the tunnel, and cover the hole so that no light enters the tunnel. When gophers see light, they start pushing soil. This will trigger the trap without catching the gopher. Traps should be checked and reset daily until no new activity occurs. Gas bombs, flooding and car exhaust are usually ineffective. Gophers can sense the water and gas. Poisons are effective, but can also cause secondary poisoning of non-target species such as domestic cats and dogs or other indigenous predators. In concept, repellents are environmentally friendly, but are not nearly as reliable. For instance, I've heard of using human hair, perfumed soaps, moth balls, and other treatments. The gopher will most likely push a soil plug into place and move on. The gopher purge plant, Euphorbia lathyris, has no proven direct effect on gophers. Some gardeners are opposed to killing any unwanted garden visitors, so they resort to live trapping and releasing the animal in another location. A few words of caution about this: the released animal has been removed from familiar territory and food sources and may die as a result. In many cases, these animals die a more inhumane death than if a lethal trap had been used. If non-lethal trapping is used, by law, the Arizona Game and Fish Department should be consulted prior to trapping to consult with you about a suitable release site. Cultural controls are those that discourage pocket gophers. These are most feasible for large areas in production agriculture and rely on habitat modifications. Examples include weed control, flood irrigation, planting crop varieties that have fewer taproots, rotation of crops, and damage resistant plant varieties. Some of these could be effective in landscape situations. Natural predators, such as bull snakes, rattlesnakes, coyotes, badgers, bobcats, and raptors can also control pocket gophers but may not always be welcome guests in the garden. The most reliable pocket gopher treatment for small areas is exclusion. This is achieved by digging a trench 24-36 inches deep, and building a barrier of sheet metal, concrete, or hardware cloth. Remember, it should also extend at least 12 inches above ground. Finally, to make you feel better about your gopher problem, you could watch the movie "Caddyshack". In that film, Bill Murray's character has several unique pocket gopher control approaches that I have not mentioned. He also had about the same success rate as the rest of us. The University of Arizona Cooperative Extension has publications and information on vertebrate pest control. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 or E-mail us at mgardener@kachina.net and be sure to include your address and phone number. |