Bacterial blight of lilac caused by Pseudomonas syringae pv. syringae.

Bacterial blight of lilac (Syringa vulgaris L.) was found in Nagano Pref., Japan. The disease first appears on shoot as water-soaked small spot. Those spots rapidly enlarge in size and become sunken, blackish and elliptical lesions. The lesions usually elongate longitudinally to form irregular-shaped stripes. Affected young shoots bend over at the lesions, wither and often die. The pathogenic bacterial isolates were identified as Pseudomonas syringae pv. syringae van Hall 1902 from the results of pathogenicity and bateriological tests.