SUGAR-CANE 87 



other plants. Allied species of this same fungus 

 occur on mango, peepul, coffee, tea, orange, lemon, 

 and other plants. 



Smut. Ustilago sacchari, Rabenhorst, or smut of 

 Bengal and Trinidad, is another stem disease which 

 causes the tip of the plant to be developed into a long 

 whip-like, much curved shoot, which may be several feet 

 in length and is a dusty black, due to the development 

 of the spores. As a rule it is not serious. It also 

 occurs on the wild Saccharum spontaneum. 



Rust. A rust due to Uredo Kuehnii, Wakker and 

 Went, occurs on the leaves of the sugar-cane in Java. 



Gumming. This disease has been reported from 

 several cane-growing districts of the world, but the 

 cause has not been determined. The tops of the plants 

 die, and in most cases the base of the arrow is found 

 to be decayed, and the disease frequently becomes 

 severe before it is recognised. Upon splitting the stalk 

 the cavities are found to be filled with a foul-smelling 

 substance and the tissues discoloured. Fresh cuts 

 bleed, producing a yellow liquid of the consistency of 

 honey which oozes from the ends of the fibres. The 

 characters of the gumming plants depend very much 

 on the length of time the plant has been diseased. 

 The drops of gum frequently run together, and contain 

 bacteria, which may be the cause of the disease. 



The disease is spread in the cuttings. Fortunately 

 many of these cuttings do not grow at all, and when 

 they do are usually tardy and make stunted plants. 



The disease can be controlled by care in the selection 

 of seed plants, the use of clean cuttings, good drainage, 

 destruction of rubbish, rotation of crops, and the 

 selection of resistant varieties. 



Calonectria gigaspora, Massee. Has been reported 

 from Trinidad as growing in the borer wounds of 

 the sugar-cane. It is very doubtful if it is of any 

 importance. 



Although the leaf diseases are not so destructive as 

 the stem and root diseases, yet they interfere with the 



