Abstract

QUIROZ-OJEDA, Claudia Milena; BOTERO-OSPINA, María José  and  CASTANO-ZAPATA, Jairo. ETIOLOGÍA DE LA NECROSIS DE LOS BROTES TERMINALES DE LA HIGUERILLA (Ricinus communis L.). Rev. acad. colomb. cienc. exact. fis. nat. [online]. 2011, vol.35, n.135, pp.133-142. ISSN 0370-3908.

Castor (Ricinus communis L.) has become a very important crop for the industry, because it is an alternative for the production of biofuel, besides of its multiple uses like the castor-oil. But, as the planting area increases, several new diseases have been detected. This research was conducted in order to identify the causal agent of the necrosis of the terminal buds or apical death, on the varieties Nordestina and Energía. To the microorganism isolated, was conducted pathogenicity tests to demonstrate the Koch's postulates and once demonstrated its pathogenicity, was determined its cultural, morphological and biochemical characteristics. The results showed that the Necrosis of the terminal shoots of castor is caused by Xanthomonas campestris, which is manifested by the presence of oily-looking patches of brown or black color in the terminal buds and young leaves, in addition to bacterial exudates. The bacterium was found in the seeds of both varieties tested, contaminating the seed coat and embryo, concluding that the seed is the primary source of inoculum of this disease.

Keywords : castor; necrosis; bud; pathogenicity; bacterium; Xanthomonas.

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