Katrine Banke Nørgaard1, Nina Cedergreen. 1. Department of Basic Sciences and Environment, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark.
Abstract
BACKGROUND, AIM AND SCOPE: The ergosterol biosynthesis-inhibiting (EBI) fungicide prochloraz can enhance the effect of other pesticides in a range of animal species. Approximately 50% of the fungicides used in Denmark are EBI fungicides. Hence, if they all have synergising potential, a risk assessment of pesticide mixtures based on additivity might not suffice. This study investigates the synergising potential of six different EBI fungicides representing the imidazoles (prochloraz), the triazoles (epoxiconazole, propiconazole and tebuconazole), the piperidines (fenpropidin) and the morpholines (fenpropimorph) together with the pyrethroid insecticide alpha-cypermethrin. MATERIALS AND METHODS: Tests were made on the aquatic crustacean Daphnia magna. Mixtures of each of the fungicides were tested together with the insecticide both at a 50:50% effect mixture ratio and, subsequently, in a ray design including five mixture ratios. The results were tested against the concentration addition reference model using dose-response surface analyses. RESULTS: The results of the binary dose-response surface studies showed that mixtures with prochloraz increased toxicity up to 12-fold compared with what was expected using the reference model concentration addition (CA). Epoxiconazole and propiconazole enhanced toxicity up to six and sevenfold, respectively. Fenpropimorph showed antagonism, whilst mixtures with tebuconazole and fenpropidin did not deviate statistically from CA. CONCLUSIONS: Hence, it can be concluded that both imidazoles and some, but not all, triazoles can enhance the effect of a pyrethroid insecticide towards D. magna substantially. Epoxiconazole and propiconazole are often sprayed out together with pyrethroids in tank mixtures. The extent to which this might create unforeseen ecological problems is discussed.
BACKGROUND, AIM AND SCOPE: The ergosterol biosynthesis-inhibiting (EBI) fungicide prochloraz can enhance the effect of other pesticides in a range of animal species. Approximately 50% of the fungicides used in Denmark are EBI fungicides. Hence, if they all have synergising potential, a risk assessment of pesticide mixtures based on additivity might not suffice. This study investigates the synergising potential of six different EBI fungicides representing the imidazoles (prochloraz), the triazoles (epoxiconazole, propiconazole and tebuconazole), the piperidines (fenpropidin) and the morpholines (fenpropimorph) together with the pyrethroid insecticide alpha-cypermethrin. MATERIALS AND METHODS: Tests were made on the aquatic crustacean Daphnia magna. Mixtures of each of the fungicides were tested together with the insecticide both at a 50:50% effect mixture ratio and, subsequently, in a ray design including five mixture ratios. The results were tested against the concentration addition reference model using dose-response surface analyses. RESULTS: The results of the binary dose-response surface studies showed that mixtures with prochloraz increased toxicity up to 12-fold compared with what was expected using the reference model concentration addition (CA). Epoxiconazole and propiconazole enhanced toxicity up to six and sevenfold, respectively. Fenpropimorph showed antagonism, whilst mixtures with tebuconazole and fenpropidin did not deviate statistically from CA. CONCLUSIONS: Hence, it can be concluded that both imidazoles and some, but not all, triazoles can enhance the effect of a pyrethroid insecticide towards D. magna substantially. Epoxiconazole and propiconazole are often sprayed out together with pyrethroids in tank mixtures. The extent to which this might create unforeseen ecological problems is discussed.
Authors: Nina Cedergreen; Anne M Christensen; Anja Kamper; Per Kudsk; Solvejg K Mathiassen; Jens C Streibig; Helle Sørensen Journal: Environ Toxicol Chem Date: 2008-07 Impact factor: 3.742
Authors: M Faust; R Altenburger; T Backhaus; H Blanck; W Boedeker; P Gramatica; V Hamer; M Scholze; M Vighi; L H Grimme Journal: Aquat Toxicol Date: 2001-12-03 Impact factor: 4.964
Authors: M Faust; R Altenburger; T Backhaus; H Blanck; W Boedeker; P Gramatica; V Hamer; M Scholze; M Vighi; L H Grimme Journal: Aquat Toxicol Date: 2003-03-17 Impact factor: 4.964
Authors: Emma R Wilson; Kelly L Smalling; Timothy J Reilly; Elmer Gray; Laura Bond; Lance Steele; Prasanna Kandel; Alison Chamberlin; Justin Gause; Nicole Reynolds; Ian Robertson; Stephen Novak; Kevin Feris; Merlin M White Journal: J Am Water Resour Assoc Date: 2014-04-01