Causal agent: Pseudomonas syringaepv. lachrymans • When cultured on Kings medium B, this organism produces a diffusible pigment that fluoresces blue under ultraviolet light • Seedborne • Spread: splashing water from rain and sprinkler irrigation
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Angular Leaf Spot • Symptoms: –Initial symptoms occur on leaves: small, irregularly shaped, water-soaked to gray-colored lesions –these lesions expand, they become angular in shape as the lesion edges become delimited by leaf veins –lesions age they turn tan to gray and become dry –The dried tissue often tears and falls out, resulting in a ‘shot hole’ or tattered appearance –conditions are wet or humid, bacterial exudates can ooze onto lesion surfaces and dry into a white residue – Lesions and bacterial ooze can also develop on petioles and stems