Cereals 



309 



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. The damage 

 is particularly serious in kafir and broom corn. See p. 283. 



These smuts 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 indication of its 

 presence. At blossoming time the fungus seeks the ovary, 

 destroys it, and becomes evident as smut. 



Disinfection of the seed by formalin is an efficient remedy. 



Head-smut ^"^^ (Sphacelotheca reiliana (Kuehn) Clinton). — 



Instead of involv- 



ing the grains 

 singly, as in the 

 kernel-smut, the 

 head as a whole is 

 affected. A white 

 membrane is at 

 first present, but 

 this later breaks 



open, exposing the 



Fig. 164. — Three views ot sorghum kernel- 

 smut. 



pulverulent spore 

 mass. Rarely, only 

 a portion of the head is smutted. The spores soon weather 

 away, leaving behind only the veins of the part involved. 

 This disease was first noted in Egypt in 1868, and is preva- 

 lent in America only in the Texas Panhandle. It occurs on 

 sorghum and to some extent on corn. Milo is immune. 



The only procedure to recommend is that employed for 

 corn smut. 



Anthracnose {Colletotrichum falcatum Went.). — Anthrac- 

 nose was first seen in America upon sorghum in North 

 Carolina, where it did consideral)le damage. It has since 

 been reported from Louisiana. The spots which are more 

 prevalent on the lower leaves have very definite gray or tan- 

 colored centers which are surrounded by dark, reddish- 



