CHAPTER V 



SUGAR-CANE 



Red Rot or Smut (Colletotrichum falcatum, 1 Went) 

 (Fig. 37). This is one of the most severe of the known 

 diseases of the sugar-cane. It was first described from Java 

 by Went in 1893. It attacks the stems and works on 

 the inside of the plant, and so cannot be detected until 

 the disease is well advanced. The first external 

 evidences of disease are the drooping, withering, and 

 finally yellowing of the upper leaves. This is followed 

 by a similar wilting of the entire crown, and finally the 

 whole stool shows indications of disease and dies. 

 When not severe the eyes frequently die and blacken 

 and the dead areas extend out from the nodes. Upon 

 splitting a diseased cane during the early stages of the 

 disease it will be found that the fibro-vascular bundles 

 near the base are reddish in colour. However, the 

 presence of .a red colour in the fibro - vascular bundles 

 is not necessarily an indication of this disease, since 

 the colour may be due to any one of many other causes. 

 As the disease advances the red colour spreads to the 

 surrounding tissues and irregular discoloured blotches 

 are formed, which may be reddish or yellowish or white 

 with red margins. These white areas with red margins 

 are a positive proof of the disease. 



An examination of the diseased tissues with a 

 microscope will reveal more or less mycelial threads of 

 a fungus, or if the diseased canes are split and put in a 



1 This organism is also said to be the cause of a root disease, but some 

 authors claim that this is not true. 



79 



