New disease of broccoli caused by Pseudomonas syringae
In 1998 and 1999, a new disease of broccoli (Brassica oleracea var botrytis) was observed in commercial crops in the Salinas Valley in California, USA. Initial symptoms consisted of large, water-soaked, dark green, angular leaf sections delimited by major leaf veins. As the disease developed affected areas turned tan and papery and leaf margins sometimes became tattered. Small round to angular spots were also present. The bacterium associated with the disease was identified as Pseudomonas syringae. Pathogenicity of 13 strains of this bacterium was demonstrated onto broccoli (Brassica oleracea var botrytis) and broccoli raab (Brassica rapa var rapa). Strains were reisolated from symptomatic tissue and identified as P. syringae. It can be recalled that a P. syringae (EPPO Alert list) was also found in commercial broccoli raab crops in the Salinas Valley (see EPPO RS 99/030). Unlike most P. syringae strains, it was observed that the strains from broccoli were sensitive to a bacteriophage recovered from P. syringae infecting broccoli raab. The authors felt that the broccoli and broccoli raab pathogens may be related.
Koike, S.T.; Cintas, N.A. (2000) Bacterial blight, a new disease of broccoli caused by Pseudomonas syringae in California.
Plant Disease, 84(3), p 370.