SCHIZOMYCETES. BACTERIA 109 



t 



are affected they may be killed. Any affected plants are prey to 

 saprophytic organisms, and an offensive soft rot is then likely to 

 result. Whether in the leaves or in the stem, the course of the 



Fig. 24. A Cabbage Leaf with Black Rot developing from Water 

 Pore Infections. (Photograph by F. C. Stewart and H. A. Harding) 



disease may usually be traced by a darkening of the fibrovascular 

 bundles. Fig. 23 shows a healthy and a diseased plant, the latter 

 as a result of artificial infection. Root infection may also occur. 



This disease has been found upon apparently all of the common 

 varieties of cabbage, in regions where the organism has gained a 

 strong foothold. Turnips, cauliflower, kale, rape, and other species 



