THE BACTERIAL DISEASE OE CORN 209 



mass of the mycelium, from which they readily separate. 

 They serve to spread the disease during a limited time 

 in Slimmer, but are supposed not to survive the winter. 

 The blackish winter spores (called by botanists the 

 teleuto-spores) are decidedly different in structure and 

 appearance from the others. A cross section of a corn 

 leaf through one of the blackish pustules is represented 

 at a, Fig. 86. As will be seen, the spores are borne on 

 stout stalks, to which they remain attached, c. The 

 spores themselves are so divided by a partition across the 

 middle that they are practically double ; each part can 

 germinate independently of the other. These spores 

 survive the winter. 



Treatment. — As already intimated, no practical 

 remedy is known for this disease ; and, fortunately, 

 none as yet is seriously needed. A more extended dis- 

 cussion of this malady is j^ublished in the 1887 report of 

 the Department of Agriculture (pp. 389-391). 



The Bacterial Disease of Corn 



In 1889 Professor T. J. Burrill, of the University 

 of Illinois, announced the discovery of a peculiar malady 

 of Indian corn, which he had proven was due to the 

 presence of bacteria. Tlie disease was then prevalent 

 over a considerable area in Illinois, and investigations 

 since have indicated that it does much damage — often 

 not understood, or else attributed to other causes — over 

 a large portion of the corn-growing region of the West. 

 As the disease is an obscure one, not easily recognized or 

 described. Professor Burrill's account of its appearance 

 is quoted below at length. 



External Manifestations. — '^ The first indication 

 of this disease in a field of corn, as noticed in ordinary 

 observation, is the dwarfed condition of the young 

 plants. This commonly occurs in spots of various sizes, 

 from a few square rods, to an acre or more, and often, 

 14 



