ISSN: 1659-2751



Identification of the Causal Agent of Bacterial Wilt of Nacedero (Trichanthera gigantea)


Nacedero (Trichanthera gigantea) is a shrubby forage crop of great importance in the diet of farm animals in the tropical regions of Latin America and Asia. An unknown destructive disease characterized by a progressive wilting and death of affected plants has been observed in Costa Rica. The main objective of this research was to determine the causal agent of the diseaseand establish its possible relationship to the bacterial wilt disease of Solanaceous plants caused by Ralstonia solanacearum. Results showed many morphological similarities between the two bacterial pathogens in colony characteristics, motility and hypersensitivity test as well as in the Gram staining reaction. Cross-inoculation tests of tomato seedlings with the nacedero bacterium and nacedero seedling with R. solanacearum did not produce any wilt symptoms, suggesting that the two bacteria were different. A confirmatory BIOLOG test at the University of Costa Rica identified the nacedero pathogen as R. pickettii.

Key words: cross inoculations, bacterial wilt, nacedero, Ralstonia solanacearum, tomato, Trichanthera gigantea.

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