VIEW ARTICLE

Evidence for Systemic Movement of Erwinia rubrifaciens in Persian Walnuts by the Use of Double-Antibiotic Markers. J. M. Gardner, Department of Plant Pathology, University of California, Davis 95616; C. I. Kado, Department of Plant Pathology, University of California, Davis 95616. Phytopathology 63:1085-1086. DOI: 10.1094/Phyto-63-1085.

Extensive systemic spread of Erwinia rubrifaciens was observed in Persian walnut cultivar ‘Hartley’. A mutant of the bacterium possessing antibiotic resistance markers for neomycin and rifampicin was used in the studies to monitor systemic spread. The bacteria spread at least 300 cm beyond the site of inoculation and remain latent in the distant symptomless regions.