Pesticides, external costs and policy options for Thai agriculture

► We quantify the external cost (EC) of pesticides in Thai agriculture using two methods. ► Using the Pesticide Environmental Accounting (PEA) tool, the average EC is USD 27 ha. ► Using an actual cost approach, the average EC is USD 19 ha. ► We discuss the pros and cons of using the PEA tool. ► We recommend combining a pesticide tax with supportive measures to change on-farm practices.