First Molecular Detection of Ramularia Leaf Spot (Ramularia collo-cygni) in Seeds and Leaves of Barley in Argentina

The fungus Ramularia collo-cygni B. Sutton & J. M. Waller (Rcc) was identified as the causal agent of this emerging disease on barley (Hordeum vulgare L.) based on symptoms and signs on leaves and attributes of the fungus. The common name given to the disease was “necrotic sprinkling.” This disease was found for the first time on barley in fields of Buenos Aires Province, Argentina, in 2001, with severities ranging from 60 to 100% (2). During the spring of 2012, the disease spread throughout most barley growing areas of the Pampean region, affecting almost all varieties of barley in the Buenos Aires, Entre Rios, and Santa Fe provinces. The disease showed typical symptoms of small, brown spots on leaves, sheaths, and awns, and caused rapid loss of green leaf area and significant economic damage. The diagnosis of this disease is difficult by conventional techniques and has caused some confusion. In order to obtain appropriate information about the incidence of this pathogen in the most important barley grow...