Pseudomonas corrugata . [Descriptions of Fungi and Bacteria

Abstract

Abstract A description is provided for Pseudomonas corrugata . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Lycopersicon esculentum . Also isolated from symptomless roots of Medicago saliva . DISEASE: Tomato pith necrosis. The pith is discoloured brown to dark brown and may show cavities, especially in the lower parts of the stem. External symptoms frequently seen include chlorosis of upper leaves, sometimes a brown to black external stem lesion where the pith is most badly affected, bacterial exudate from leaf scars, pruning and other wounds, and on older plants prolific development of adventitious roots on the stems in areas where the pith is most badly affected. GEOGRAPHICAL DISTRIBUTION: South Africa, New Zealand (cultures at CMI), Denmark (62, 6), England, Germany (East 60, 5559; West 61, 6591), Italy (S. Sardinia 63, 1960), USA (CA 62, 2155; F 62, 3656; PA 59, 919 on Lucerne). The distribution is probably much more widespread than these records show. TRANSMISSION: The bacterium is probably common in the environment. It has, for example, been isolated from mains water which was being used to irrigate an affected crop. It is probably also spread from plant to plant by man in cultural operations. The disease is favoured by high humidity or wet foliage and high nitrogen levels in the soil; conditions that favour soft plant growth that is most susceptible.