CANE SUGAR. 



infected parts are covered with an abundant mucus mycelium, and eventually a 

 large number of sclerotia the size of a pin's head are produced ; these are first 

 white, and finally become yellow and brown. The diseased parts have a smell 

 of mushrooms. It is young cane that is most often attacked, and in the case 

 of tops the germination of the eyes may be prevented. 



3. Add Rot of the Leaf SJieafh A disease much resembling the Eed 

 Rot, and also incompletely diagnosed. It is distinguished by the lighter red 

 colour of the infected parts, by the larger sized orange 

 sclerotia, and by the odour of apples. The disease 

 does not readily pass to the stem, and then only 

 attacks the young internodes. 



Diseases of the Stem. 



1. Black Smut. Ustilago saccJiari. Rabenhorst. 

 The organism which causes this disease is found in 

 all affected parts. The part of the cane most liable to 

 attack is the top of the young cane, which is turned 

 into a black, whip-like substance, covered with a 

 slimy foul-smelling material ; the whole stool of cane 

 is destroyed. The organism is found on grasses and 

 on wild cane, the latter in Java having been noted 

 as a source of infection. The disease occurs in Java, 

 Natal, Queensland, and India, where Butler has 

 observed the possibility of the disease appearing 

 from the use of infected tops; he does not consider 

 it a dangerous disease, but the writer has seen 

 great damage caused in Mauritius. In one case a 

 seven-acre field was absolutely destroyed. Butler also 

 observes that the fungus has a predilection for those 

 varieties of cane approaching wild cane. The 

 technical description of this fungus is: Sorts atris : 

 Sports globosis sulawgulatis, 8-18 olivaceo-bruneis, vel 

 rufescentibus, episporio crasso levi imtructis. In Fig. 67 is shown the whip-like 

 appearance of the cane attacked by this disease, and in Fig. 68 spores of the 

 fungus. 



2. Donkelan-ziehte. u Mar- 

 asmius sacchari. Wakker. This 

 is a disease attacking the foot of 

 the cane, and, so far as regards 

 Java, appearing chiefly in nur- FIG. 68. 



series. The disease is characterized by the withering of the leaves of the 

 young shoots, and by the non-development of the buds. The cane plants 

 contain in the interior a mycelium which also occurs as large white flakes 

 on the surface of the cane. The fungus has been studied in the West 



FIG. 67. 



142 



