The Bacterial Diseases of the Bean 81 



found throughout the United States, as reported by Miss Hedges (1926). 

 It has been isolated also, by the same investigator, from seed both from 

 France and from Germany. 



Phytomonas medicaginis var. phaseolicola was first observed in New 

 York by the writer (Burkholder, 1926), and recently Miss Hedges (1928) 

 has reported it from Montana, Wyoming, and Colorado in the West, and 

 from Florida, Georgia, and South Carolina in the South. In Europe, 

 M. K. T. Wieringe has isolated the pathogene in Holland, and the writer 

 has obtained it from diseased bean pods collected in Switzerland. 



Phytomonas phaseoli var. fuscans has been found in Switzerland caus- 

 ing a disease of the common bean, and Miss Hedges has isolated the 

 organism from seed imported from South America. 



Phyto?no7ias vig?iae var. leguminophila has been found only in New 

 Jersey and in New York. 



Phytomonas viridiflava was isolated from pods collected in a market at 

 Lucerne, Switzerland, and a similar organism was found causing a leaf 

 spot of the scarlet runner bean near Canterbury, England. 



CONTROL METHODS 

 The same control measures have been advocated for the various bacterial 

 diseases of the bean, since the diseases are alike in many respects and 

 since the life histories of the pathogenes are similar, all being seed-borne 

 diseases. In New York the blights due to Phytomonas phaseoli and Phyt. 

 medicaginis var. phaseolicola are the bacterial diseases which cause eco- 

 nomic losses, and consequently are the ones with which control measures 

 are especially concerned. The methods applied in holding in check 

 these two diseases, however, appear to be effective against the other 

 bacterial diseases of the bean also. These methods of control, which 

 have been successful when applied, are two in number: first, the use when 

 possible of bean varieties showing some resistance to the blights; and 

 secondly, the use of disease-free seed in all cases. Rands and Brotherton 

 (1925) have published a paper dealing with the varietal susceptibility of 

 many varieties of beans to Phyt. phaseoli and Phyt. flaccumfaciens; and 

 the writer (Burkholder, 1924) has reported on similar experiments with 

 Phyt. phaseoli. Observations in the field and on inoculation work in 

 the greenhouse leads to the belief that there is a close resistance correla- 

 tion among the various bacterial diseases. Consequently, the use of 

 any of the varieties listed in the above-mentioned articles as somewhat 

 resistant will probably eliminate much of the trouble from all of these 

 diseases. In New York, among the field beans or those frequently referred 

 to as the dry shell beans, the Robust Pea bean shows considerable resist- 

 ance to these bacterial diseases. Also, in the fields the blights seldom 

 cause much damage to Yellow Eye, and White Marrow is not extremely 

 susceptible. With reasonable precautions in selecting the seed to be 

 planted, one should have little trouble with these varieties. 



