OVERVIEW AND RATIONALE FOR DEVELOPING REGULATORY GUIDELINES FOR NONTARGET PLANT-TESTING WITH CHEMICAL PESTICIDES

In the assessment of ecological risk posed by pesticide use, much greater emphasis has been given to the direct effects on wildlife than on impacts on wildlife habitat. Assessment of indirect effects to wildlife entails an evaluation of pesticide toxicity to plant species (and invertebrates) that make up wildlife habitats. Under the pesticide registration process in Canada and in most other countries, there is no specific requirement for testing the toxicity of pesticides to nontarget plants other than agronomically important species. The proposed nontarget plant testing guidelines summarized in this paper are intended to fill this gap. The chief objectives of the guidelines are to outline data requirements, to suggest methods and approaches for generating the data required, and to facilitate and improve hazard assessment for nontarget plants (and habitats) as a result of chemical pesticide use. The rationale behind decisions reached in the guidelines is also presented. The proposed guidelines are very flexible, as registrants may be granted a waiver for any test required, provided the rationale is justified on appropriate scientific grounds. Harmonization and comparison with other guidelines are discussed. These proposed nontarget plant testing guidelines can serve as a basis for guideline development or modernization for other jurisdictions.