Toxicity of the herbicide glyphosate to Chordodes nobilii (Gordiida, Nematomorpha)

CECILIA L. ACHIORNO,; CRISTINA DE VILLALOBOS; LUCRECIA FERRARI

CHEMOSPHERE

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2008 vol. 71 p. 1816 - 1822

0045-6535

Nematomorpha (horsehair worms) is a poorly known group of worm-like animals similar to nematodes. Adults are free-living andreproduction takes place in freshwater environments, where preparasitic larvae undergo development. All species have a parasitic juvenilstage and infection may result in the host’s death, insects being the most frequent host. Most of the life cycle occurs in freshwater environments,which are often contaminated by different pollutants. Based on the lack of information on the toxicity of herbicides to horsehairworms, the objective of this study is to evaluate the effect of different concentrations of glyphosate (technical grade and formulatedproduct) on Chordodes nobilii (Gordiida, Nematomorpha). Bioassays were performed with embryos and larvae (preparasitic stages), andadults (postparasitic stage). Test organisms were exposed for a short period of time to concentrations ranging between 0.1 and8 mg a.e. l1 of glyphosate (technical and formulated). Although embryo development was not inhibited, there was a significant decreasein the infective capacity of larvae derived from eggs that had been exposed to P0.1 mg/l. Similar results were obtained for directlyexposed larvae. No differences in toxicity were detected between the active ingredient and formulated product. Adult exposed for96 h to 1.76 mg l1 formulated Gly shown a mortality of 50%. Results indicate that C. nobilii is affected at glyphosate concentrationslower than those expected to be found in freshwater environments and those specified in the legislation.Published by Elsevier Ltd.Keywords: Nematomorpha; Chordodes nobilii; Glyphosate; Bioassays; Infection index