853 



cent, the liigliest being 17.7 per cent. Ou the whole the resnlts are 

 considered sufficiently favorable to warrant the continuation of experi- 

 ments in this line. 



Diseases op the sugar beet root, J. C. Arthur, D. Sc, and 

 K. E. Golden, B. S. (pp. 54-62, plate 1).— A report on observations on 

 three diseases of the beet root, viz, a bacterial disease, beet scab, and 

 water core spots. 



A hacteridl disease of beet roofs. — Late in the season of 1890 micro- 

 scopic examinations nuidc at the station revealed the presence of bac- 

 teria in beets hii\ing a low percentage of sugar. More extended 

 observations during tlie following year showed that beets of diflereut 

 varieties grown in different parts of Indiana were quite generally 

 affected by the same disease. Analyses showed that the diseased beets 

 contained nuich less sugar than the healthy roots. 



The beet root sliows externally no marks by wliieb the ])reseiice of the bacterial 

 parasite can be detected; the most diseased and the strictly healthy roots can not be 

 separated by any external characters. This statement, however, does not apply to the 

 leaves. While the plants are small the foliage of healthy and diseased plants remains 

 normal, bnt as the plants reach full size, and especially as they approach maturity, 

 those which are most affected can be told at a glance by the alteied ai)pearance of tho 

 leaves. The healthy beet leaf has a decidedly dat, nuiform surface, while the diseased 

 leaf is puffed out between the veins in little blister-like areas, giving the general 

 appearance of the surface of a Savoy cabbage leaf. Diseased plants are necessarily 

 less vigorous than healthy ones, and the fact is made apparent to the eye as the season 

 advances by the leaves becoming paler and smaller, and the outer ones dying away 

 faster than those upon healthy plants. All these imlications taken together, most 

 reliance being placed upon the crinkled surface, will enable one to select such 

 diseased plants, as they are growing in the held, with considerable certainty. But 

 some roots not showing the foliar characteristics to any marked extent will also be 

 found to be affected. 



Upon cutting across a root the most constant indication of the malady is a greater 

 prominence of the fibers which form the concentric rings. In well-marked cases each 

 microscopic bundle shows as a dark dot, the circlesof dots growing more distinct upon 

 exposure to air. In less pronounced cases the woody fibers are merely yellowish or 

 even quite coloiless, but become more prominent than normal tissues after being 

 exposed to the air for a while. Furthermore, the diseased root is rather soft and tough 

 and of a yellowish white color, while a iiealthy root is firm, somewhat brittle, and 

 clean white in color. It has also been found that diseased root*) are lighter in 

 weight than healthy ones. - f * 



While the bacteria are most abundant and conspicuous in the colorless parenchyma, 

 they also occur iu the cells of the tibro-vascular bundles, and in the green cells of the 

 leaf — in fact in all parts of the plant. 



The bacteria are all of one shape and appearance, Ijeing nearly twice as long as 

 broad, small, oblong, colorless, usually occurring as isolated cells, although occa- 

 sionally found in pairs. 



Pure cultures have been studied in the laboratory, being isolated by the well-known 

 plate method. The sejiaration is easily accomplished, as the large size of the roots 

 pei'mits the removal of pieces of tissue from well below the surface, and consequently 

 free from soil and air contamination, and from such material only one form of microbe 

 is obtained. 



Iu a Pasteur sugar culture the bacteria grow well, causing the licjuid to become 

 slightly turbid in 24 hours. As growth goes on the turbidity becomes greater, and 



