Resumen

MAIDANA OJEDA, Marco; CHAMORRO, Natalia; BARZALA, Marta  y  FRETES, Edgar. First report of black spot in yerba mate (Ilex paraguariensis A. St.-Hill) Caused by Calonectria sphatulata in Paraguay. Investig. Agrar. [online]. 2016, vol.18, n.2, pp.111-115. ISSN 2305-0683.  https://doi.org/10.18004/investig.agrar.2016.diciembre.111-115.

In the last 5 years, yerba mate (Ilex paraguariensis A. St.-Hill.) export doubled and its demand in the domestic market increased from 15 to 20%, this has encouraged an increase on production area thus favoring the spread of pathogens that cause crop´s phytosanitary problems. The aim of this study was to diagnose leaf black spot, a disease caused by Calonectria sphatulata (anamorfo: Cylindrocladium spathulatum) on the leaves of yerba mate. During the 2014-2015 harvest, in the municipalities of Carlos Antonio Lopez, San Rafael del Paraná, Mayor Otaño and Tomas Romero Pereira, a sampling of yerba mate leaves with symptoms of black spot was carried out. Symptoms description and quantification of defoliation on affected plants was done in field. In laboratory, using fresh samples, purified strains of fungus in PDA culture medium were isolated.

Identification was done by observation in a light microscope and using descriptive keys. In field, the observed symptoms start as a black point which grows in circular fashion until reaching 2 cm in diameter on leaves older than 12 months with severe defoliation, but without plant death. In laboratory, the morphological characteristics observed in the isolated corresponded to Calonectria sphatulata. This is the first report of this pathogen in Paraguay in yerba mate plantations.

Palabras clave : Morphological identification; Cylindrocladium spathulatum.

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