Hypoaspis (Geolaelaps) aculeifer is considered to be a relevant representative of soil fauna and predatory mites in particular. It is worldwide distributed and can easily be collected and reared in the laboratory.
Synchronized adult females of Hypoaspis aculeifer, of 28-35 days after the start of egg lying period, are exposed to the test substance mixed into the artificial soil by an appropriate carrier or sprayed on the soil surface in order to evaluate the effects on reproduction and other sublethal effects. Reproduction performance is assessed after 2 weeks of exposure.

TEST SYSTEM
Hypoaspis (Geolaelaps) aculeifer
A toxic reference substance is tested once a year to check the sensitivity of the organisms.

STUDY DESIGN
Range finding test includes 5 concentrations of the test substance and 1 untreated control (2 replicates/treatment or control) with 10 females/replicate.
Limit test is carried out with 1 concentration of the test substance and 1 untreated control (8 replicates/treatment or control) with 10 females/replicate.
Rate-response test for NOEC/LOEC evaluation includes at least 5 concentrations of the test substance and 1 untreated control (4 replicates/treatment and 8 replicates for the control) with 10 females/replicate.
Rate-response test for EC_x evaluation includes 12 concentrations of the test substance and 1 untreated control (at least 2 replicates/treatment and 6 replicates for the control) with 10 females/replicate.
Rate-response test for EC_x and NOEC/LOEC evaluation is performed with 8 concentrations of the test substance and 1 untreated control (4 replicates/treatment and 8 replicates for the control) with 10 females/replicate.

ENDPOINTS
Mortality: LC_x or LOEC/NOEC after 2 weeks of exposure.
Reduction in reproduction: EC_x or NOEC/LOEC after 2 weeks of exposure.
Study includes GLP management and reporting.

REFERENCES AND GUIDELINES
OECD Guideline fo Testing of Chemicals, No. 226 (29^th July  2016) – Predatory mite (Hypoaspis (Geolaelaps) aculeifer) reproduction test in soil.