Trap the Gopher to Kill It
Many pest control experts recommend lethal trapping as the best way to control gophers. You have to dig a lot, and you have to check traps regularly, but you do not have to handle poisonous gases or baits, nor do you have to chase after loose gophers with a shovel. Two types of traps are commonly used: “squeeze” or “body gripping” traps, which catch the animal between a set of strong jaws, and “box” traps, which are safer to handle. Trapping is best done in spring or fall, when gophers are most active. For best results, follow these steps:
Locate a fresh lateral tunnel or a main tunnel by probing the ground with a metal rod. Dig an opening into the tunnel and set two traps inside, one oriented in each direction, on either side of your opening. This ensures that a gopher will trip a trap in either direction. Bait the traps first with a bit of strong-scented vegetable such as onion or scallions or leeks. Be sure to handle the traps with gloves on for safety and to mask any human scent.
Tie each trap to a cord and secure this to a nearby stake. To help lure the gopher into the traps, cover the opening with a board or plug it and fill with some soil to seal off any light. It may help to use something tasty, such as a bunch of lettuce leaves, as a plug. If the gopher sees light, or senses that something is amiss, he will promptly seal off the tunnel but may avoid springing the trap as he works.
Check the traps once or twice daily, because gophers often patrol their tunnels. If you detect nothing after 48 hours, reset the traps in another tunnel. Bury or dispose of any dead gophers right away.
Fumigate the Gopher
If you do not feel like digging a lot of holes to set traps, you can try fumigating the gophers first. Injecting poisonous smoke into the tunnels may kill the pests where they sit or drive them out to be killed on the surface. In either case, the smoke will reveal all the tunnel exits, when you can seal off quickly.
The Exhaust Method: This requires a gasoline powered mower or tiller. Obtain a length of flexible metal exhaust hose from an auto supply store. Make sure it is of sufficient diameter to fit your motor’s exhaust pipe. Start your motor. Expose a main tunnel and insert one end of the hose into it, then tamp soil around it to seal it. Then apply a few drops of oil just inside the other end, put on gloves, and affix this to the motor’s hot exhaust pipe. Allow the motor to idle for 15 to 30 minutes. Quickly seal any tunnel openings that allow smoke to escape. The carbon monoxide should kill any gophers trapped below.
The Flare Method: A simpler method is to open the tunnel and shove a lighted highway flare into the hole, then seal all the entrances as above. The noxious sulfur fumes will drive the gophers into the open, where they can be killed with a shovel.
Commercial gas cartridges or “bombs” are also available Some of these are toxic, some are not. Read the package labels carefully. Some of these fumigants, such as highly toxic aluminum phosphide, are best left to professional pest control experts. In any case, never fumigate soil in areas that lie close to occupied buildings, as the poisonous gases may seep into the basement or crawl spaces.
Drown the Gopher
The gopher’s tunnel system is complex and spreads through a considerable underground area. However, gophers are poor swimmers and can be drowned by vigorous flooding of tunnels. This method works best if the tunnel system is not highly developed. Locate the main gopher burrow by probing the soil with a sturdy metal rod or large screwdriver. This probe should encounter the tunnel from 6 to 18 inches below the soil surface; you will know you are there when the probe suddenly drops about 2 inches. Once the main tunnel has been located, smash down all other mounds with a shovel. Then dig an opening in the main tunnel, insert a garden hose into it, and tamp a soil seal around it. Turn on the water and watch for gophers to emerge, when they can be killed. Depending on the extent of tunneling and the type of soil, it will take 15 minutes to an hour before there is enough water in the tunnels to drown any young and flush out the adults.
Avoid Using Poisons
Several products are available at hardware and garden centers for poisoning gophers. They consist of grain or pelleted material dosed with strychnine or an anticoagulant. These are placed at several points in the main tunnel. They should be used only during a dry period, because they tend to deteriorate under moist conditions.
Note: Using poisoned baits risks secondary poisoning of other animals. Poisoned gophers may wander about on the surface, to be eaten (and poisoned in turn) by predators or household pets such as cats. Depending on your situation, it may be wiser to trap the gophers instead. Whichever poison bait you use, store it in a safe place away from children and pets. Carefully follow the package directions for use.
Tip: Forget the chewing gum. Many folks think that feeding gophers a few sticks of chewing gum (Wrigley’s Juicy Fruitä brand seems to be favored) will kill them. Tests have shown that the gophers may eat the gum but are not harmed by it. Save this treat for yourself.
Encourage Gopher Predators
Gophers have many natural enemies, which may help you in your battle to rid the yard of these persistent pests. Certain snakes of the genus Pituophis (bull snakes, gopher snakes, and pine snakes) are fond of gophers. Other predators include cats, dogs, king snakes, skunks, barn owls, badgers, weasels, foxes, hawks, raccoons, bobcats, and coyotes.