VIII. THE BEAN BLIGHT 

 (Syn. The bacterial bean spot) 



Type. This is a disease of beans common on leaves, stems 

 and pods, and confined principally to the parenchyma although 

 the vessels also are invaded, sometimes for a distance of several 

 inches. It occurs on several species of beans (Phaseolus) and 

 is a serious disease. Whether other related genera are subject 

 remains uncertain. Similar looking bacterial diseases occur 



FIG. 213. Portion of under surface of an immature bean leaflet showing 

 stomatal infections (light spots) due to a pure culture spray inoculation 

 of Bacterium phaseoli isolated from an Idaho bean. Time, 3 days. Spots trans- 

 lucent but not yet brown or sunken. Planar enlargement by James F. Brewer, 

 September 26, 1914. X 8. 



on cowpea (Vigna) and on soy bean (Mucuna), but my cross- 

 inoculations to plants of these genera failed (one trial only, 

 but using many plants and virulent cultures sprayed on the 

 foliage). A yellow organism resembling this one on agar and 

 potato was plated from spots on leaves of the soy bean in my 

 laboratory in 1902 from Charleston, South Carolina, and Wash- 

 ington, D. C., and again in 1917 from Norfolk, Virginia. 



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