SCHIZOMYCETES. BACTERIA 119 



a bacterial disease of the oleander in California, and from cul- 

 tural characters of the organism isolated, as well as from inocula- 

 tion experiments, he considers this organism to be Pseudomonas 

 Olece. On the other hand, Erwin Smith would regard this as 

 improbable, since he obtained no infections on oleander. He 

 would seem to suggest that the organism isolated in California 

 may have been the organism of crown gall (see p. 114). 



VI. BEAN BLIGHT 

 Pseudomonas Phaseoli Erw. Smith 



BEACH, S. A. Bean Blight. N. Y. Agl. Exp. Sta. Kept. 11 : 553-555.' 1892. 



SMITH, ERW. F. Description of Bacillus Phaseoli, n. sp. Proc. Am. Assn. 

 Adv. Sci. 46: 288-290. 1897. 



SMITH, ERW. F. The Cultural Characters of Four One-Flagellate Yellow Bac- 

 teria Parasitic on Plants. U. S. Dept. Agl., Div. Veg. Phys. and Path. 

 Built. 28 : 1-153. 1901. 



WHETZEL, H. H. Some Diseases of Beans. Cornell Agl. Exp. Sta. Built. 

 239: 197-214. figs. 100-115. 1906. 



The bean blight, a disease far more common and destructive 

 in the United States than has been generally believed, is due to 

 this organism. The disease is common 

 upon field, garden, and lima beans. It 

 affects leaves, stems, and pods, but par- 

 ticularly the leaves and pods, upon which 

 the symptoms are also most conspicuous. 

 It is believed that diseased seed is the 

 source of many early infections, whereas 

 later infections may result through wounds 

 in any green parts. On the foliage there 

 appear irregular water-soaked patches, 



which later become, during dry weather, FlG - 2 9- PSEUDOMONAS 

 brown and papery. The disease pro- J|jJkSSS! 

 gresses slowly, therefore it becomes evi- 

 dent, as a rule, only when the pods begin to form. Control is 

 difficult, and must concern itself largely with seed selection 

 and crop rotation. Seed from an affected field should not be 

 planted. It is not enough to attempt to sort out healthy seed, 

 when some of the lot are evidently diseased, for many which 

 show no discoloration will be penetrated by the bacteria. 



