The effects of different concentrations (0.2, 2, 20, 200mgl(-1)) of two sterol biosynthesis inhibitor (SBI) fungicides, i.e. fenpropimorph and fenhexamid, were evaluated on the spore germination, germ tube elongation, sporulation, and root colonization of Glomus intraradices grown monoxenically in association with transformed carrot roots. The percentage of germinated spores incubated on the SBI fungicides and the length of the germ tubes decreased with increasing concentrations of both fungicides. However, for spore germination this impact was fungistatic rather than fungicidal. Extraradical mycelium architecture and spore production in contact with the SBI fungicides were also strongly impacted at high concentration (20mgl(-1)). Conversely, the colonization of roots developing in the fungicide-free compartment, but interconnected with the extraradical mycelium developing on the SBI fungicides, appeared unaffected. Our results demonstrated that the monoxenic culture system could be used as a standardized, reproducible technique to compare the impacts of different molecules on arbuscular mycorrhizal fungi, and for the initial screening of new candidate molecules before registration.
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http://dx.doi.org/10.1016/j.mycres.2007.11.010 | DOI Listing |
Environ Pollut
November 2024
Behavioural Physiology and Sociobiology, Biocenter, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
Plant protection products (PPPs), which are frequently used in agriculture, can be major stressors for honeybees. They have been found abundantly in the beehive, particularly in pollen. Few studies have analysed effects on honeybee larvae, and little is known about effects of insecticide-fungicide-mixtures, although this is a highly realistic exposure scenario.
View Article and Find Full Text PDFIn agricultural environments, bees are routinely exposed to combinations of pesticides. For the most part, exposure to these pesticide mixtures does not result in acute lethal effects, but we know very little about potential sublethal effects and their consequences on reproductive success and population dynamics. In this study, we orally exposed newly emerged females of the solitary bee Osmia cornuta to environmentally-relevant levels of acetamiprid (a cyano-substituted neonicotinoid insecticide) singly and in combination with tebuconazole (a sterol-biosynthesis inhibitor (SBI) fungicide).
View Article and Find Full Text PDFProc Biol Sci
March 2024
School of Environmental Sciences, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
Mounting evidence supporting the negative impacts of exposure to neonicotinoids on bees has prompted the registration of novel 'bee-friendly' insecticides for agricultural use. Flupyradifurone (FPF) is a butenolide insecticide that shares the same mode of action as neonicotinoids and has been assessed to be 'practically non-toxic to adult honeybees' using current risk assessment procedures. However, these assessments overlook some routes of exposure specific to wild bees, such as contact with residues in soil for ground-nesters.
View Article and Find Full Text PDFEnviron Sci Technol
October 2023
Vietnam National University, Ho Chi Minh City, Quarter 6, Linh Trung Ward, Thu Duc City, Ho Chi Minh City 700000, Vietnam.
Hymexazol is a volatile fungicide widely used in agriculture, causing its abundance in the atmosphere; thus, its atmospheric fate and conversion are of great importance when assessing its environmental impacts. Herein, we report a theoretical kinetic mechanism for the oxidation of hymexazol by OH radicals, as well as the subsequent reactions of its main products with O and then with NO by using the Rice-Ramsperger-Kassel-Marcus-based Master equation kinetic model on the potential energy surface explored at the ROCBS-QB3//M06-2X/aug-cc-pVTZ level. The predicted total rate constants (, ) for the reaction between hymexazol and OH radicals show excellent agreement with scarcely available experimental values (e.
View Article and Find Full Text PDFEcotoxicol Environ Saf
May 2023
University of Würzburg, Behavioral Physiology and Sociobiology (Zoology II), Am Hubland, 97074 Würzburg, Germany. Electronic address:
The increasing loss of pollinators over the last decades has become more and more evident. Intensive use of plant protection products is one key factor contributing to this decline. Especially the mixture of different plant protection products can pose an increased risk for pollinators as synergistic effects may occur.
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