Proceedings of the Vertebrate Pest Conference

The common valley pocket gopher (Thomomys bottae) has become a serious agricultural pest in certain regions of the Lower Colorado River Basin. The mechanical burrow-builder is the most economical and effective method of controlling this pest, although many growers and some researchers have reported less-than-satisfactory results when using this technique with currently available rodenticides. Six formulations of three toxicants including strychnine, zinc phosphide, and diphacinone were applied with the burrow-builder to assess their efficacy. Results indicated that negligible control is achieved with 0.35 and 0.5% strychnine, although these are the most commonly used formulations in Arizona. Diphacinone also produced negligible control. Zinc phosphide was clearly the most effective of the compounds tested with 45% control achieved. More work with this compound is warranted.