title: Acute toxicity of three strobilurin fungicide formulations and their active ingredients to tadpoles.
abstract: Fungicide applications in the United States have increased tenfold in the last 5 years. Formulations and active ingredients (AIs) have been demonstrated to cause acute mortality to amphibian life stages. However, there has been little to no discrimination between the toxicity of fungicide formulations and their AIs. Therefore, we compared the acute toxicity of the active ingredients and formulations of the fungicides Headline®, Stratego®, and Quilt® using Bufo cognatus tadpoles exposed to four concentrations and a control. All fungicides, including AIs and formulations, demonstrated toxicity to tadpoles, with Headline® and Stratego® causing 100 % mortality at the highest concentrations. Exposure to Quilt® formulation and its AIs resulted in 50-60 % tadpole mortality. Overall, toxicity was comparable between AIs and formulations for all fungicides and concentrations, with the exception of Headline® at 5 μg/L, where formulation exposure resulted in 79 % mortality versus no mortality from exposure to the AI. Results suggest the AIs are responsible for most mortality for Quilt® and Stratego®. Results for Headline® however suggest that although the AI is toxic to tadpoles at environmentally relevant concentrations, adjuvant(s) in the Headline® formulation also contribute to mortality, making it the most toxic of the fungicides studied.
authors.affiliation: Department of Zoology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK 74078, USA. Emily.Hooser@okstate.edu
authors.forename: Emily A
authors.initials: EA
authors.lastname: Hooser
authors.forename: Jason B
authors.initials: JB
authors.lastname: Belden
authors.forename: Loren M
authors.initials: LM
authors.lastname: Smith
authors.forename: Scott T
authors.initials: ST
authors.lastname: McMurry
mesh_terms: D000085:Acetates / Q000032:analysis / Q000633:toxicity*; D000818:Animals; D002025:Bufonidae / Q000254:growth & development*; D002219:Carbamates / Q000032:analysis / Q000633:toxicity*; D004338:Drug Combinations; D004781:Environmental Exposure / Q000032:analysis*; D005659:Fungicides, Industrial / Q000032:analysis / Q000633:toxicity*; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D011720:Pyrazoles / Q000032:analysis / Q000633:toxicity*; D011786:Quality Control; D000073739:Strobilurins; D023382:Toxicity Tests, Acute; D014230:Triazoles / Q000032:analysis / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity
chemical_list: D000085:Acetates; D002219:Carbamates; D004338:Drug Combinations; D005659:Fungicides, Industrial; D011720:Pyrazoles; C556296:Stratego; D000073739:Strobilurins; D014230:Triazoles; D014874:Water Pollutants, Chemical; C513428:pyrachlostrobin