Commercial Fungicide Toxic Effects on Terrestrial Non-Target Species Might Be Underestimated When Based Solely on Active Ingredient Toxicity and Standard Earthworm Tests

Abstract

The ecosystem services provided by earthworms are lost when land management reduces their populations, hence, the importance of thorough assessments of management effects on this group. The present study aimed to: (1) review the possible influence of other ingredients within the formulations of two commercial fungicides; (2) assess the sublethal effects of these commercial fungicides on Eisenia fetida; and (3) assess the acute lethal effects of one commercial fungicide on both Glossoscolex rione and E. fetida. Examining all components of the studied commercial formulations revealed that alongside the toxic active ingredients are other ingredients that are equally as or more toxic than the former and may even be in higher concentrations. The inhibition concentration of 10% of E. fetida’s progeny (IC10) was estimated at 133 mg kg−1 for PROSARO® and 1544 mg kg−1 for SWING PLUS®. Both fungicides showed an effect of hormesis on the progeny. In this first toxicity study with G. rione, it was found that this species is more sensitive to PROSARO® than E. fetida, with preliminary 14 day-lethal concentrations of 285 mg kg−1 for the former and >1000 mg kg−1 for the latter.