Chemical control of faba bean rust (Uromyces viciae-fabae)

The effectiveness of eleven foliar-applied fungicides on faba bean rust (Uromyces viciae-fabae (Pers.) J. Schröt.) and on the seed yield of faba bean (Vicia faba L.) were studied in growth chambers and in the field in Spain. Fungicides were tested at recommended and reduced rates. All the fungicides tested provided very effective preventive control in the growth chamber studies. Triazoles (difenoconazol, epoxiconazol, tebuconazol) and their mixtures with benzimidazoles (carbendazim-flutriafol and carbendazim-flusilazole) provided the most effective curative effect, even at 25% of recommended concentrations. They were followed by dithiocarbamates, copper dithiocarbamate mixture, carboxamide and chlorothalonil. Triazoles, benzimidazole-triazole mixtures and carboxamide maintained their effect until 15 days after fungicide application.Under field conditions, rust infection caused 22-26% yield reduction. All fungicides except mancozeb caused a significant decrease in disease severity under field conditions, but only treatments with triazoles and benzimidazole-triazole mixtures provided significant yield increases (22.7-15.6%) when applied twice. Three applications of oxycarbosin or copper-mancozeb were needed to provide a significant yield increase. Dithiocarbamates (thiram, maneb or mancozeb) or chlorothalonil reduced rust severity but did not provide a significant yield increase. © 2011 Elsevier Ltd.Financial support by Spanish projectsAGL2008-01239 and AECID-D/026716/09 is acknowledged.Peer Reviewe