308 Diseases of Economic Plants 



sorghum, broom corn, Kafir corn, and Milo maize, and 

 has been noted in IlHnois, Kentucky, Iowa, Louisiana, 

 Ohio, Michigan, Nebraska, West Virginia, and District 

 of Columbia, often in serious form. The chief character 

 is irregular-shaped, elongated blotches of red, at first faint 

 orange, upon the leaves and leaf sheaths, sometimes limited 

 by the veins, and always more conspicuous on the inner 

 than the outer sides. Smaller patches later blend, and the 

 affected parts die and finally turn black. The lower sides of 

 diseased spots upon the leaves often bear red incrustations, 

 resulting from the dr3ang of the exudate from within. The 

 roots show the same discoloration, and the outer parts of the 

 rootlets die and become loose. If only slightly diseased, the 

 plants may attain normal size. 



Badly diseased roots are evidenced by the yellowed tops 

 and other signs of malnutrition. In advanced stages the 

 roots give such poor anchorage that the plants may be easily 

 pulled from the ground. 



Infected stalks should be burned and such rotation fol- 

 lowed as to relieve the infested soil of susceptible crops for 

 several years. 



Kernel-smuts^'^- (Sphacelotheca sorghi (Lk.) CI., S. cruenta 

 (Kuehn) Potter) . — These smuts infest the individual grains 

 of the panicle, while the head as a whole remains nearly 

 normal in appearance. The smutted grains are at first 

 covered by a white, later gray, membrane. This membrane 

 in time becomes broken by the winter exposure and frees the 

 dark-colored spores. 



Kernel-smut was reported by Kellerman in 1891 as limited 

 to sorghum grown from imported seed. It was then known 

 in the District of Columbia, Wisconsin, New York, Nebraska, 

 and Kansas. It is widespread in Europe, Africa, and Asia, 

 and was probably imported into the United States upon 

 diseased seed. It was first recorded in the United States in 

 1884, and is now found in almost all places where sorghum is 

 grown. 



According to Clinton's estimates it may prevail upon 



