Chapter 27

Vineyard Wildlife Control

Gophers

Gophers can cause long-term damage if left unchecked in the vineyard. Gnawing on grapevine roots and trunks will lead to large patches of dead vines. Gophers can also damage irrigation systems and cause erosion by diverting water via their burrows. Although these pests have natural predators, growers should not rely on them solely for controlling large populations of vertebrates. Many tools are available for controlling gophers including trapping, baiting, fumigation, and birds of prey.

Management Guidelines

To successfully control gophers, the sooner you detect their presence and take control measures the better. Most growers control gophers in vineyards by trapping, by using poison baits and by using barn owls.

Trapping

Effective and efficient trapping of pocket gophers requires three key elements. First, use plenty of traps. Set at least one trap for every fresh mound in the vineyard. Second, carefully inspect the vineyard to determine the location of the newly constructed mounds. Newly constructed mounds tend to be taller, have more granulated soil that is less compacted, and darker color. Mounds that are flattened with light tan coloration are old mounds and should be avoided. Third, trapping requires patience and effort.

Baiting

For large populations, several rodenticides for controlling pocket gophers in vineyards have been registered with the federal government and are in current use. To be effective, pocket gopher baits must be placed in the main underground tunnel, not the lateral tunnels. After locating the main gopher burrow with a probe, enlarge the opening by rotating the probe or by inserting a larger rod or stick. Use a funnel to place the bait carefully in the opening, taking care not to spill any on the ground.

Fumigation

Many fumigants are not very effective against gophers due to their ability to detect and seal off tunnels quickly. However, aluminum phosphide (a Restricted Use Material) works well during the late winter or early spring months when the soil is moist.

Barn Owls

Growers have had some success in controlling gophers, voles, and field mice in vineyards with barn owls. However, this approach requires providing artificial nest boxes in vineyards to encourage barn owls to habitate (See Figure 27.4). Design of the box, placement, number, and maintenance all influence roosting and rodent control success. Boxes provide both a place for barn owls to roost in the fall and a safe nesting spot to raise their family of owlets in the spring.

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