Seed dressing pesticides on springtails in two ecotoxicological laboratory tests

• The toxicity of seed dressing pesticides was tested on springtails.
• Acute and chronic tests were performed in laboratory.
• All pesticides caused mortality in Folsomia candida.
• Only imidacloprid and fipronil showed negative effects in the chronic toxicity test.
• The acute toxicity assays were considered useful to define the sublethal concentrations.

Terrestrial ecotoxicological tests are powerful tools for assessing the ecological risks that pesticides pose to soil invertebrates, but they are rarely used to evaluate seed dressing pesticides. This study investigated the effects of seed dressing pesticides on survival and reproduction of Folsomia candida (Collembola), using standardized ecotoxicological tests (after ISO guidelines with few adaptations for tropical conditions). Commercial formulations of five seed dressing pesticides were tested individually in Tropical Artificial Soil (TAS): the insecticides imidacloprid, fipronil, thiametoxam, and the fungicides captan and carboxin+thiram. Thiametoxam, captan, and carboxin+thiram were only lethal to F. candida at the highest concentration tested (1000 mg of active ingredient kg−1 of dry soil). Imidacloprid and fipronil were lethal at lower concentrations (100 and 10 mg a.i. kg−1 soil d.w, respectively), however, these concentrations were much higher than those predicted (PEC) for soil. Imidacloprid and fipronil were the most toxic pesticides in both tests, reducing significantly collembolan reproduction (EC20=0.02 and 0.12 mg a.i. kg−1 soil d.w, respectively). Further studies under more realistic conditions are needed, since imidacloprid and fipronil reduced collembolan reproduction at concentrations below or close to their respective PECs.