Acute and repeated exposure toxicity of the insecticide sulfoxaflor on hymenopteran pollinators; sulfoxaflor environmental science review part III

To support regulatory risk assessment, standardized laboratory tests of toxicity to representative species including honeybees (<i>Apis mellifera L.)</i>, orchard bees (<i>Osmia spp</i>.), and bumblebees (<i>Bombus spp</i>.) provide the benchmark toxicity values for use in preliminary Tier 1 assessments and more detailed and realistic higher-tier assessments. In this analysis, we summarize the results of studies of toxicity of SFX to pollinators conducted registrant as well as results published in the literature. The geometric mean of 48-hr adult acute oral LD₅₀ values for SFX for honeybees was 0.0740 μg SFX bee^{− 1} (<i>n</i> = 5). Toxicity values for technical grade SFX (SFX-T) and formulated products were not significantly different. The geometric mean 48 hr adult acute contact LD₅₀ values for SFX-T and several formulated products were 0.432 (<i>n</i> = 2) and 0.202 (<i>n</i> = 3) μg SFX bee^{− 1}, respectively. Exposures sprayed foliage was not significant after the spray had dried did not cause significant toxicity. Transformation products were not significantly toxic to adult or larval honeybees or other representative bee species. Results showed that, to complete the risk assessment, higher-tier studies were required. Differences in results between standard test methods and the nonstandard methods used in published work affect the outcome of the risk assessment. An understanding of these differences reconciled the differences in the reported findings.