Eficacia de tres estrobilurinas para el control de mancha rojiza (Guignardia mangiferae) y mancha negra (Guignardia citricarpa) en frutos de limón, en Tucumán, República Argentina

argentina leads lemon world production and industrialization. the province of tucumán generates 87% of national production, processing 65% of this production in factories and commercializing 35% as fresh fruit, mainly for exports, which requires high quality, disease-free fruits. two fungal species of guignardia are present in tucumán: one is g. citricarpa (phyllosticta citricarpa) and the other is g. mangiferae (p. capitalensis). the former is the causal agent of citrus black spot, a quarantine pathogen for major consumer markets, and the latter is a cosmopolitan fungus which causes red spot in lemon in tucumán. both diseases are controlled with copper, strobilurins, mancozeb, and benzimidazols. five field experiments were conducted to evaluate the efficacy of three strobilurins, azoxystrobin, pyraclostrobin and trifloxystrobin, to control red spot (during the 2004/2005, 2005/2006 and 2006/2007 crop seasons) and citrus black spot (in the 2007/2008 and 2008/2009 seasons) in lemon fruits in tucumán. one or two applications of strobilurins were made with copper oxychloride, in a program of four or five copper applications, every thirty days from petal fall. treatments with copper oxychloride, alone or mixed with mancozeb, were used as chemical controls. the most effective treatments were those that included one or two strobilurin applications, without differences between them. they outdid copper treatments, equaling or surpassing copper-mancozeb mixture. these results demonstrated the efficacy of strobilurins to control both black spot and red spot in lemon.