As almond trees have shed their blooms and trees are leafing out, it’s time for growers to turn their attention to one of the most vexing orchard problems: pocket gophers. This is the best time to focus control efforts because gophers are more easily identified from mounding in moist soils.
As Roger Baldwin, wildlife pest management advisor with the UCCE Statewide IPM Program, reported at the 2012 Almond Conference, integrated management that takes advantage of a number of available tools is the best way to control this vertebrate pest. Growers should be aware of recent changes to regulations and products when it comes to integrating these control methods.
Baiting is a good method for knocking down gopher populations in large areas as a follow-up with additional control measures.
Strychnine baits have historically provided the most effective bait control for pocket gophers; however, due to a strychnine shortage in recent years, the 1.8% formulation is no longer available.
While growers may opt for the lower 0.5% strychnine bait or other bait options such as anticoagulants, Baldwin said there have not been studies on these materials to show they are effective for pocket gophers.
Burrow fumigation with aluminum phosphide is the most efficacious of all pocket gopher control options, providing 95% control. Baldwin said fumigants should be applied when soil moisture is high to improve efficacy.
There have been several recent label changes to registered aluminum phosphide products, and Baldwin cautioned growers to carefully read and follow label instructions and consult the county ag commissioner with questions. Among the changes, growers now must post treated areas for 48 hours, and fumigants cannot be applied within 100 feet of a structure, which may limit treatments on orchard perimeters.
Trapping is very effective as a follow-up to target remaining pests after other treatments. Baldwin compared the Gophinator and Macabee traps, finding the Gophinator the more effective because it traps more large-sized gophers.
He also looked at capture rates for covering trap sites in spring/summer and fall, and found that slightly higher capture rates did not justify the added time and expense.
More from Western Farm Press