A plunge in the world’s population of frogs and toads may be blamed, at least in part, on farm pesticides, researchers in Germany said on Thursday.
Tests of fungicides and insecticides, when used at recommended dilutions, killed 40 percent of frogs after seven days, and in one case, 100 percent of them after just one hour, they said.
The experiments, which entailed only a small number of animals, were carried out by a team led by Carsten Bruehl at the University of Coblenz-Landau in Germany.
They collected 150 juvenile European common frogs (Rana temporaria) to expose them to seven agricultural products, the goal being to reproduce in the lab conditions which were akin to those in the field.
The frogs were kept in large containers with soil where barley was grown. The chemical was sprayed once, delivering a volume that the researchers said was equal to the amount that would fall on a similar area of an arable field.
There were three kinds of doses: recommended concentrations; one-tenth of recommended concentrations; and 10 times recommended concentrations.
The most toxic substance, according to the study, was Headline, used to prevent fungus in soybeans and wheat. At recommended dosage, it killed all of the tested frogs within one hour.
Only five frogs were assigned to each experiment, and the animals were used cautiously out of ethical considerations.
- Researchers: Pesticides causing dramatic die-off in frog population worldwide (rawstory.com)
- Researchers: Pesticides causing dramatic die-off in frog population worldwide (sott.net)
- Pesticides ‘can kill frogs within an hour’ (guardian.co.uk)
- New research shows common pesticides can kill frogs within an hour (dgrnewsservice.org)
- Common Pesticides ‘Can Kill Frogs Within an Hour’ (commondreams.org)
- Common Pesticides ‘Can Kill Frogs Within an Hour’ (earthfirstnews.wordpress.com)
- Rethink pesticide ban, Manitoba PC leader urges province (cbc.ca)
- Claim: Common pesticides ‘can kill frogs within an hour’ (junkscience.com)