95 . 



per cent, for diseased ones, a lo6s of nearly 50 per cent, of the sugar content. 

 The per cent, of sugar is expressed in terms of the beet, not of the juice. 



Besides the bacterial disease that is general for all parts of the plant, the 

 sugar beet roots are afft?cted with diseases of a local character. These are 

 in the form of surface scabs, discoloration of the tissue, and small masses of 

 tissue different from that surrounding them. 



The scabs are of two kinds, one resembling the so-called "deep scab" of 

 potatoes, while the other protrudes from the surface. 



The deep scabs are light brown in color wljen first affecting the root, but 

 as the root is more deeply affected they become dark brown or rusty black. 

 They vary in size from a mere dot to an extent sufficient to nearly cover 

 the whole root, though the latter case is not so often found. The deep 

 scabs are sometimes accompanied by a red discoloration of the tissue that, 

 in some cases, extends fully two inches beneath the surface. Upon expos- 

 ure to the air the red color changes to magenta. These scabs are not to be 

 confounded with the breaks in the surface of the roots caused by uneven 

 growth. 



The raised scab differs essentially from the preceding in outward appear- 

 ance, as it forms warty elevations on the surface of the roots. It has the 

 same general color as the deep scabs, but has not been found covering so 

 great an extent of surface as they. When found in large quantity, instead 

 of extending itself over the surface, it seems to have a tendency to form 

 bands encircling the root. It is oftenest found near the neck of the beet at 

 or near the surface of the ground. Both forms of scab are found on the 

 same root, sometimes in close proximity, and forms have been found seem- 

 ingly intermediate between the two. It is probable that the two forms of 

 scab are just different stages of the same disease ; the raised scab being the 

 first stage, where the irritated tissue with the corky modifications form ele- 

 vations on the surface of the root ; as the tissue outside the corky layers 

 dies and is gradually eliminated, the depressions are left in the surface. 

 This theory is given further force from the fact that the same organism has 

 been obtained from plate cultures of both forms of scab. The organism has 

 the characteristic of the potato scab germ described by Dr. Thaxter.* There 

 are the same filamentous forms that break up into bacteria-like bodies, and 

 the dark stain given to the culture medium. 



The organism itself is perfectly colorless, but it excretes a substance 



*Annual Report Conn. Agr. Exp. Sta., 1890, pp. 81-95. 



