Pest Management Science (2019) 75, 1847-1854

Roger A. Baldwin, Heather Halbritter, Ryan Meinerz, Laura K. Snell and Steve B. Orloff (2019)
Efficacy and nontarget impact of zinc phosphide-coated cabbage as a ground squirrel management tool
Pest Management Science 75 (7), 1847-1854
Abstract:
BACKGROUND
Effective management of ground squirrels relies on an integrated pest management (IPM) approach. Rodenticides may be included in an IPM program, but they must be efficacious with minimal impact on nontarget species. A zinc phosphide-coated green bait may meet these requirements. We established a study in northeastern California to test zinc phosphide-coated cabbage as a management tool for Belding's ground squirrels (Urocitellus beldingi). We specifically addressed factors that would influence the efficacy of a baiting program, as well as potential exposure risk to nontarget species.
RESULTS
We found that prebaiting was an important application strategy, and efficacy increased as ground squirrel abundance increased. Efficacy was also greater in western portions of the study area, likely due to greater bait consumption at western sites. Belding's ground squirrels fed most heavily on cabbage during mid-morning and late afternoon; bait applications shortly before these time periods would increase bait consumption while minimizing nontarget risk. Bait uptake was greatest around burrow entrances. The only nontarget species observed feeding on cabbage was the California kangaroo rat (Dipodomys californicus), although they were never observed feeding on treated cabbage.
CONCLUSION
Zinc phosphide-coated cabbage can be an efficacious tool for managing ground squirrels, but there will be limitations on where and how it can be used effectively. It posed a low risk to nontarget species present in our study area, but nontarget risk could vary regionally. The use of a zinc phosphide-coated green bait should only be one part of an IPM strategy for managing ground squirrels.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Roger A. Baldwin

Research topic(s) for pests/diseases/weeds:
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Urocitellus beldingi		U.S.A. (SW)