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 grea ter emphasis has been given to the direct effects on wildlife than on impacts on wildlife habitat. Assessment of indirect effects to wildlif e entails an evaluation of pesticide toxicity to plant species (and in vertebrates) that make up wildlife habitats. Under the pesticide regis tration process in Canada and in most other countries, there is no spe cific requirement for testing the toxicity of pesticides to nontarget plants other than agronomically important species. The proposed nontar get plant testing guidelines summarized in this paper are intended to fill this gap. The chief objectives of the guidelines are to outline d ata requirements, to suggest methods and approaches for generating the data required, and to facilitate and improve hazard assessment for no ntarget plants (and habitats) as a result of chemical pesticide use. T he rationale behind decisions reached in the guidelines is also presen ted. The proposed guidelines are very flexible, as registrants may be granted a waiver for any test required, provided the rationale is just ified on appropriate scientific grounds. Harmonization and comparison with other guidelines are discussed. These proposed nontarget plant te sting guidelines can serve as a basis for guideline development or mod ernization for other jurisdictions.