Advances in Research on Phytophthora Palmivora, Causal Agent of Bud Rot of oil palm in Colombia
Bud rot of oil palm has been the most devastating disease, not only in Colombia, but also in neighboring countries like Brazil, Ecuador, Panama and Suriname. The disease symptoms are characterized by rotting of all the new tissue, with the preservation of the leaves that were formed before the infection. The internal symptoms show the destruction al the young spear leaves, without damage to the meristematic area, at least in early stages of the rotting process. In the region the cause of the disease was unknown for more than 40 years, but as a result of the recent research of the scientists at the Colombian Oil Palm Research Centre - Cenipalma it was possible to identify Phytophthora palmivora Butl., as the causal agent of the first lesions that promote the development of the rotting process which begins in the young immature tissue of spear leaves that are developing above the meristem. This pathogen was isolated in palms in early stages of development of the disease, in the zone of advance of the lesion toward the meristem, in the three main growing areas in which samples were taken. The development of the lesions in the tissue is very characteristic and can be used for the early diagnosis of the disease. In older palms it is easier to see the damage of the tips of the leaflets that produce a bite like appearance. In some cases there is remission of symptoms. It has been possible to recover infected palms removing the affected tissue and protecting the palms with a wide range of fungicides, bactericides and insecticides. As a result of this research it has been possible to isolate the pathogen in pure cultures, to observe its development, to identify chlamydospores in the infected tissue in the three studied zones in Colombia, in culture media and in the lesions produced in the pathogenicity tests done in vitro and in young palms in the field. The morphology of the caducous sporangia, that are papillate with a short pedicel, has been one of the most important characteristic that leaves no doubt that the pathogen is P. palmivora (Genebank accession GQ398157). It was also possible to carry out molecular characterization of at least three of the isolates that confirmed the identification of the microorganism. It is still not very clear if the differences between the lethal and the non-lethal forms of the disease are related with different environmental growing conditions of the oil palm, or with a pathogenic characteristic of the microorganism , or if further development of the disease is related with the different opportunistic microorganisms that colonize the affected tissue or is due to the damage done by some insects, that feed and reproduce in the bud area of oil palm, as per example Rhynchophorus palmarum.
| Main Authors: | , , , , , |
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| Format: | Digital revista |
| Language: | spa |
| Published: |
Fedepalma
2010
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| Online Access: | https://publicaciones.fedepalma.org/index.php/palmas/article/view/1472 |
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