VIEW ARTICLE

Colonization and Movement of Pseudomonas syringae on Healthy Bean Seedlings. Curt Leben, Visiting Research Plant Pathologist, Department of Plant Pathology, University of California, Berkeley 94720; M. N. Schroth(2), and D. C. Hildebrand(3). (2)(3)Associate Professor, and Associate Research Plant Pathologist, respectively, Department of Plant Pathology, University of California, Berkeley 94720. Phytopathology 60:677-680. Accepted for publication 7 November 1969. DOI: 10.1094/Phyto-60-677.

Pseudomonas syringae was recovered from terminal buds and from newly unfurled leaves and stipules of healthy bean seedlings 9-22 days after buds were inoculated and seedlings were placed in a humid atmosphere. The pathogen also was recovered from these leaves and stipules after plants were in a less humid atmosphere for 7-16 additional days. In other tests, P. syringae spread over the wet leaf lamina within 2 days after the lamina was inoculated at one point near the petiole junction. Motility of the pathogen and physical forces could account for movement on individual leaves. Under suitable conditions in nature, we suggest (i) that there is epiphytic colonization of healthy buds by P. syringae; (ii) that from this source the pathogen may be distributed on newly forming plant parts as the plant grows; and (iii) that motility of the pathogen and physical forces result in additional spread on the plant when it is wet.