CEREALS 



363 



ance. 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. 



The disease was reported by Kellerman in 1891 as limited 

 to sorghum grown from imported seed. It was then known 

 in District of 

 Columbia, Wis- 

 consin, New 

 York, Nebraska, 

 and Kansas. It 

 is widespread in 

 Europe, Africa, 

 and Asia, and 

 was probably im- 

 ported 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 

 from 4 to 32 per cent of the plants. The same investigator 

 found that the yield in juice was lessened about 30 per cent, 

 owing to the smaller size of the smutted plants. 



As with oats, this smut can gain entrance to the host only 

 during the very young seedling state, before the plants 

 appear above ground. The mycelium of the causal fungus 

 grows through the plant until flowering time without any 

 symptoms of its presence. At blossoming time the fungus 

 seeks the ovary, destroys it, and becomes evident as smut. 



Disinfection of the seed is an efficient remedy. The seed 



Fig. 158. — Three views of sorghum kernel smut. 

 Original. 



