Evaluating Rodenticide Use Impacts on Agricultural Production

Abstract

It is widely recognized that vertebrate pests cause serious economic losses by reducing agricultural production and by adding to production costs when control programs are conducted. Despite this, most vertebrate pest control programs are implemented without accurate knowledge of the potential losses prevented or the relevant economic benefits accrued from specific control strategies. One method of evaluating potential benefit/cost of vertebrate pest control is to establish the actual vertebrate pest damage sustained and compare that to control costs assumed necessary to prevent the vertebrate damage. This approach suffers from several shortcomings, including: (1) inherently large inputs required to assess damage over a large area; (2) limitations because data are influenced by current control programs; and (3) vertebrate damage averaged over large areas often appears small compared to other production costs, despite the fact that some crops (locations) may be intensively damaged. One method of overcoming these problems is to determine rodenticide use patterns, that is, type and quantity of material used, target species, and acreage and value of crops treated, and relate these to potential or theoretical crop protection. A range of damage levels can be used to develop “what if” scenarios relating to specific crops and target species. These create a picture of the potential protection afforded by the specific control program. While considerable efforts are required to obtain this data, they serve to demonstrate the theoretical value of a particular rodenticide or control program. This information is extremely important to regulators and others making decisions affecting current vertebrate pest control programs. Such an approach has been used to illustrate the impact of rodenticide use in one California county.