The Bacterial Diseases of the Bean 59 



range, which would keep them from being considered identical. Phyt. 

 vignae is described as producing an abundant growth on potato cylinders 

 and causing no change in the color of this medium. In Fermi's solution 

 it produces a green-yellow pigment. The organism dealt with here will 

 barely grow on potato, and causes the medium to turn gray; and in Fermi's 

 solution a white, milky growth is produced. The differences are not great, 

 but they do show that the two pathogenes are not the same. 



There is a more pronounced difference in their pathogenicity, however. 

 With Phyt. vignae, Gardner and Kendrick (1925) obtained negative results 

 on garden beans, soybeans, and broad beans. Infection was produced in 

 all of these species by the organism under consideration here. So suscep- 

 tible are the garden bean and also the broad bean, that there could be no 

 mistake concerning this character. Consequently it is felt that this is a 

 distinct pathogene, although one closely related to the cowpea organism. 

 For these reasons it is held as a variety of Phyt. vignae, and because of its 

 broad host range is given the name Phytomonas vignae var. leguminophila 

 n. var. 



Brief description 



Phytomonas vignae var. leguminophila is a non-spore-forming rod with 

 rounded ends, occurring singly or in pairs. The cells measure 1.35 to 

 3.6m by 0.6 to 1.8ju. The organism is motile by means of one to two 

 polar flagella. It is Gram-negative, not acid-fast, and a facultative 

 anaerobe. 



The colonies on beef-extract agar (pH 7.0) are round, white to hyaline, 

 smooth and amorphous, with the edges entire, producing a water-soluble 

 green fluorescent pigment; nutrient broth is cloudy within twenty-four 

 hours; gelatin liquefaction is fairly rapid; milk turns alkaline, clears, and 

 later becomes muddy; litmus is reduced; a green fluorescent pigment 

 appears in Uschinsky's solution; there is a white milky growth in Fermi's 

 solution; starch is not digested; growth is very slight on potato; acid is 

 produced in dextrose and in saccharose broth, but none in lactose or in 

 maltose broth; gas is not produced in these sugar broths; indol is not 

 produced; nitrates are not reduced to nitrites; hydrogen sulfide is not 

 produced or but slightly; the thermal death-point is approximately 49° C. 



The organism is pathogenic on the common bean (Phaseolus vulgaris) 

 and on a number of closely related species. 



A HITHERTO UNREPORTED BACTERIAL DISEASE OF THE BEAN, FROM 



EUROPE 



(Caused by Phytomonas viridiflava n. sp.) 



In August, 1927, green-bean pods were observed in a market in Lucerne, 

 Switzerland, showing lesions which, from appearances, were due to a 

 bacterial invasion. The lesions were rather reddish brown in color, and 



