Resumo

GARCIA-LEON, Elizabeth et al. Identification and incidence of three phytopathogenic fungi of new report on oat (Avena sativa L.) at Mexico's central plateau. Agrociencia [online]. 2013, vol.47, n.8, pp.815-827. ISSN 2521-9766.

Stem rust and crown rust in oat crops (Avena sativa L.) are the most destructive diseases in most of the world. In addition, the incidence of foliar diseases caused by a complex of pathogen fungi is increasing. During the spring-summer agricultural cycles in 2009 and 2010, severe symptoms of leaf blight were observed in commercial plots sown with oat, at the states of Hidalgo, Tlaxcala, Puebla, Morelos, Estado de México and Distrito Federal, México. The objectives of this study were to identify the causal agents of leaf blight in oats, as well as to determine their incidence and distribution in the high valleys of México's Central Plateau. Leaves with leaf blight symptoms were collected from 63 sites during the 2009 cycle and 100 sites in 2010. The determination of causal agents of the diseases was performed through Koch postulates. Using a morphological and molecular analysis, as well as pathogenicity tests, Alternaria alternata, Bipolaris victoriae and Bipolaris sorokiniana were identified as the causal agents for leaf blight. The frequencies of fungi were 20.85, 12.26 and 9.2 % of the total of sites visited. This is the first report of these species of phytopathogenic fungi on oat at México. The incidence of the three fungi was greater in the 2010 cicle and its distribution was in oat fields of Tlaxcala, Hidalgo, Estado de México, and Distrito Federal. The importance of the presence of these fungi is that they are pathogens that can decrease production and produce mycotoxins that are harmful to livestock consuming oat as fodder.

Palavras-chave : Avena sativa; Alternaria alternata; Bipolaris victoriae; Bipolaris sorokiniana; Cochliobolus.

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