46 



FUNGOID DISEASES 



smut, is one of the most objectionable diseases of 

 cereals. It destroys a number of ears, and at thrash- 

 ing the remaining healthy grains 

 become covered with the black 

 spores, thus spoiling the taste and 

 colour of the flour made therefrom ; 

 while the straw and chaff are made 

 distasteful to stock. 



Symptoms . — It is only with 

 difficulty that bunted ears can be 

 distinguished from healthy ones at 

 harvest time. The bunted ears 

 are broader, the glumes more open, 

 and the grains have a greyish colour 

 (see Fig. ii). The opening of 

 the glumes is due to the increased 

 breadth of the bunted ^rain en- 

 cased within (Fig. 12, B). Some- 

 times the grains are cracked ; this 

 reveals the inner contents, viz. a 

 black mass of spores of the fungus. 

 These spores have a strong fishy 

 odour due to the presence of tri- 

 methylamine. 



Catise. — The bunted orrains are 

 caused by the formation of the 

 spores of the fungus (Zl Tritici) from mycelium 

 which had entered the wheat plant in the early 

 stage and grown up with it. 



I'lG. II. — A diseased 

 ear of wheat show- 

 ing the dark col- 

 oured bun ted grains 

 enclosed within the 

 glumes (somewhat 

 diagrammatic). 



