Occurrence of bacterial blight of fenugreek caused by Pseudomonas syringae pv. syringae and isolation of the pathogen from infested seed

Fenugreek, recently introduced in New Jersey, is an annual legume grown as a specialty crop and for forage use in North America. A leaf spot and blight of fenugreek was observed for the first time in New Jersey fields during the growing season of 2000. Isolations from diseased plants consistently recovered a bacterium that was fluorescent on King's B agar. Reinoculation of the bacterium on fenugreek in greenhouse studies resulted in the appearance of symptoms similar to those observed in the field. Taxonomic characterization resulting from biochemical and physiological tests, Biolog GN2 microplate, 16S rDNA, and fatty acid methyl ester analyses identified the bacterium as Pseudomonas syringae pv. syringae. PCR amplification of syrB and syrD gene specific fragments confirmed isolates as P. syringae pv. syringae. Host range studies using other leguminous plants indicated the fenugreek strain was virulent on pea, but was avirulent on snap bean, soybean, and alfalfa. The bacterium was isolated from a seed lot used in New Jersey that resulted in diseased plants, suggesting seed as the probable source of the pathogen.