• Research in Plant Disease
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• v.15 no.3
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• pp.183-186
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• 2009

Leaf spot symptoms were observed in a commercial Palenopsis cultivated fields. Circular-elliptical watersoaked spots surrounded by a light green or yellow halo and turned to black when it was severe infection or blacken with gathered symptoms. These spots were finally enlarged to form of larger areas. Under the favorable conditions of temperature and moisture, the infection extended rapidly and dispersed to the crown and sometimes the infected plant became dead. A bacterial organism, isolated from the advancing margins of the lesions, was tested to characterize causing bacterium based on pathogenicity. The biochemical and physiological tests of that bacterium identified that as an Acidovorax avenae subsp. cattleyae. Therefore, we suggested to call that the new Phalaenopsis disease was bacterial brown spot caused by A.avenae subsp. cattleyae in Korea.