Bacterial brown spot of bean
| Pseudomonas syringae | |
|---|---|
| Bacterial brown spot of bean | |
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| Cultures of Pseudomonas syringae | |
| Scientific Classification | |
| Kingdom: | Bacteria |
| Phylum: | Proteobacteria |
| Class: | Gamma Proteobacteria |
| Order: | Pseudomonadales |
| Family: | Pseudomonadaceae |
| Genus: | Pseudomonas |
| Species: | Pseudomonas syringae |
| Pathovar: | Pseudomonas syringae pv. syringae |
| Synonyms | |
| Bacterial brown spot Bacterial brown spot of bean |
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Bacterial brown spot of bean is the most economically significant disease of processing beans in the north-central region of the United States. It also occurs in other bean-growing areas of the United States and the world. The bacterium can on plant debris for 1 year.[1]
Symptoms[edit | edit source]
Bean[edit | edit source]
Small 3-9mm (⅛-⅜in), oval, necrotic lesions are apparent on leaves. A narrow yellow-green zone of tissue may be seen surrounding the lesions. Bacterial exudate (ooze) and water-soaking are rarely observed prior to necrosis. The leaf tissue around the lesion may be puckered. Lesions coalesce and their centres fall out, giving leaves a tattered appearance.[1]
On pods, dark brown lesions are generally small, 1-3mm (less than ⅛in) in diameter, necrotic and cause pod malformation by inciting cessation of growth by nearby tissue.[1]
Control[edit | edit source]
Spray weekly with copper-containing chemicals after symptoms have been observed, particularly when weather is overcast, cloudy and humid and especially when these conditions follow rain or irrigation.[1]
Prevention[edit | edit source]
Resistant varieties of beans are available. Crop rotation should be practiced.[1]


