Evaluation of the extraction efficiency for the Hypoaspis aculeifer reproduction test in the context of soil quality assessment.

The standardized bioassay using the predatory mite Hypoaspis aculeifer (TG 226; as reported by OECD 2008) has already proven its usefulness for the assessment of chemicals. While included in the regulatory assessment scheme of pesticides as a non-target arthropod, it has still been rarely used for the assessment of soils or complex matrices of unknown quality. For such an objective, the extraction of both adults and juveniles from soil is a necessary and crucial step to get reliable data, but may be influenced by the characteristics of the tested soils or matrices. This technical note focuses on this specific protocol point. Extraction ratios of adults and of different reproductive outputs were evaluated in soils of different textures. Recommendations on the extraction of H. aculeifer in the standardization process within ISO/TC 190 are here provided.