344 



Bulletin 163. 



large bell glass. On Sept. 2 all of the inoculated plants were dis- 

 eased, but the trouble had not spread from the bell glasses. 



Experiment 3. Twelve beets as above were inoculated, but 

 with no provision for retaining moisture. On Sept. 2 nine of the 

 inoculated plants were affected. 



Experiment 4. Twelve beets were inoculated with a mixture 

 of several bacterial forms isolated from diseased tissues and from 



51. — The bt'ozvn hyphce which invest the cracks on diseased beets. 



parts of the beet immediately below diseased areas. These beets 

 remained healthy throughout the experiment. 



Alternating with the rows experimented upon were check 

 rows, all of the beets in which remained perfectl}^ free from root- 

 rot troubles. 



These experiments indicated that the fungus Rhizoctonia read- 

 ily produces root-iot when the conditions are favorable, and that 

 moist conditions are essential for the spread of the disease from 

 plant to plant. Later experiments with pure cultures of the 

 fungus growing on bean pods were used to inoculate seedling 

 beets, and with such plants a damping off effect was produced. 



