404 Eeport op the Mycologist of the 



various stages of the disease are intermingled with apparently 

 healthy plants of different sizes. It is a common thing to find 

 diseased plants in the same hill -vNdth healthy ones which may 

 continue in good heaJth to the end of the season. There are no 

 indications that the disease is communicated from one plant to 

 another. It does not spread from an initial center, but is scat- 

 tered all through the field. Ilsually, the small plants are the first 

 to succumb to the disease, which fact suggests that the disease 

 may be the cause of their slow growth. This suspicion was con- 

 firmed by microscopic examination. Plants green and apparently 

 healthy, except for their small size, were found to contain a con- 

 siderable quantity of the bacterium in their vessels, while in the 

 larger, more vigorous plants the bacterium could not be found. 

 However, in wet weather the bacterium may sometimes be found 

 in quite vigorous plants. This feature of the disease will be dis- 

 cussed more fully on a subsequent page. 



The bacterium invades the vessels of all parts of the plant, 

 including the roots. Plants which did not succumb to the dis- 

 ease until after the ears had commenced to form were examined 

 after they were dead but before they were completely dry, and 

 the bacterium was found in abundance in the vessels of all parts 

 of the stem clear up to the tassel and in the ear, where it oozed 

 out onto the kernels and the inner husks. The ears showed no 

 tendency to rot. 



BACTERIA THE CAUSE OF THE DISEASE. 



Since affected plants behave very much like plants suffering 

 from lack of moisture, except that there is little or no " rolling '-' 

 of the leaves, ■careless ohservers are liable to think that dry 

 weather is the cause of the trouble. This theory is at once 

 rendered untenable by the fact that plants die from the disease 

 in wet weather as well as in dry weather. Some have attributed 

 the trouble to the fertilizer used, but one does not have far to 

 seek to remove suspicion from the fertilizer. It is also easily 

 demonstrated that insects are not responsible for it. Various 

 species of fungi may be found on the roots of dead plants but no 



