Variation in toxicity among formulations and species makes it difficult to extrapolate results to all species and all formulations of herbicides. The authors exposed larval wood frogs (Lithobates sylvaticus) from 4 populations to 2 glyphosate-based herbicides, Roundup Weed and Grass Control® and Roundup WeatherMax®. The 96-h median lethal concentration values for both formulations varied among the populations (Roundup Weed and Grass Control, 0.14 mg acid equivalents (a.e.)/L to 1.10 mg a.e./L; Roundup WeatherMax, 4.94 mg a.e./L to 8.26 mg a.e./L), demonstrating that toxicity varies among the formulations and that susceptibility may differ among populations.
Keywords: Amphibian; Aquatic toxicology; Glyphosate; Herbicide; Roundup; Variation.
© 2014 SETAC.