A two years field experiment to assess the impact of two fungicides on earthworm communities and their recovery.

Abstract Recent EFSA (European Food Safety Authority) reports highlighted that the eological risk assessment of pesticides needed to go further by taking more into account the impacts of chemicals on biodiversity under field conditions. We assessed the efects of two commercial formulations of fungicides separately and in mixture, i.e., Cuprafor Micro® (containing 500 g kg−1 copper oxychloride) at 4 (C1, corresponding to 3.1 mg kg−1 dry soil of copper) and 40 kg ha−1 (C10), and Swing® Gold (50 g L−1 eoxiconazole EPX and 133 g L−1 dimoxystrobin DMX) at one (D1, 5.81 10−2 and 1.55 10−1 mg kg−1 dry soil of EPX and DMX, respectively) and ten times (D10) the recommended field rate, on erthworms at 1, 6, 12, 18 and 24 months after the application following the international ISO standard no. 11268-3 to determine the efects on erthworms in field situations. The D10 treatment significantly reduced the species diversity (Shannon diversity index, 54% of the control), anecic abundance (29% of the control), and total biomass (49% of the control) over the first 18 months of eperiment. The Shannon diversity index also decreased in the mixture treatment (both fungicides at the recommended dose) at 1 and 6 months after the first application (68% of the control at both sampling dates), and in C10 (78% of the control) at 18 months compared with the control. Lumbricus terrestris, Aporrectodea caliginosa, Aporrectodea giardi, Aporrectodea longa, and Allolobophora chlorotica were (in decreasing order) the most sensitive species to the tested fungicides. This study not only addressed field eotoxicological efects of fungicides at the community level and eological recovery, but it also pinpointed some methodological weaknesses (e.g., regarding fungicide concentrations in soil and statistics) of the guideline to determine the efects on erthworms in field situations.