ABSTRACT


Bernardo A. Latorre1 y Fernando Nome H.2
 
The survival of Corynebacterium michiganense (Smith) Jensen, causal organism of tomato bacterial canker, was studied under field conditions in two types of soils belonging to the Santiago and Graneros soil series int he Chilean central valley. The soil were artificially infected with rests of diseased tomato plants. Tomatoes were planted inmediately after infection and five, ten, and twelve months later to evaluate the persistence of the causal organism. In the Santiago soil series the inoculum survived for ten months and in th Graneros series, for twelve.The main symptoms were wilting and chlorosis of the plant and internal necrosis of the main stem. The percentage of diseased plants obtained was statistically significant. From these results it can be concluded that the survival of the causal organism notably decreases after being soil inoculated and this is associated with time elapsed from infection. Data showed that the bacteria lives saprophytically in the soil when inoculated through rests of diseased tissues. This phenomenon is significant since the occurance of one single diseased plant in a field is sufficient to initiate an epiphytotic.
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1Ing. Agr. Profesor Ayudante de las Cátedras de Fitopatología General y Patología Forestal, Facultad de Agronomía, Universidad de Chile, casilla 1004, Santiago, Chile.
2Ing. Agr. M. S. Profesor de la Cátedra de Fitopatología General, Facultad de Agronomía, Universidad de Chile. Dirección actual: Universidad Nacional de Córdoba, Insituto de Ciencias Agronómicas, casilla 509, Argentina.