CANE SUGAR. 



As regard parasites, Treub 41 ascribed the disease to the attacks of a 

 nematode worm to which he gave the name Heterodera javanica. Coinciding 

 with the attacks of this worm he observed the presence of a fungus of the 

 genus Pythium. This worm penetrated the bark of the root at places of 

 accidental injury or at the growing point. After having arrived within the 

 root the worm worked its way parallel to the central axis until it arrived at 

 the point of growth of a lateral root. Soltwedel 42 also attributed the damage 

 to attacks of a worm to which he gave the name Tylenchus sacchari, 

 stating that the parasite passed its existence in the root which it destroyed. 

 The length of the Tylenchus is given by Soltwedel as about '7 mm. and its 

 breadth as about '03 mm. 



The connection between nematode worms and Sereh is not now generally 

 accepted. 



Janse 43 ascribed the cause of Sereh to two organisms, 

 Bacillus sacchari, and Bacillus glanga, and stated that these 

 organisms attack other plants besides the cane. He considered 

 the seat of the disease lay in the reddened nbro-vascular bundles. 

 The dependency of Sereh on these organisms is not now 

 generally accepted. 



Lastly, Went attributed Sereh to a combined leaf-sheath 

 and root disease, caused by an organism Hypocrcea sacchari, the 

 description of which is as follows : 



Pulvinata dein depressa, carnosa, pallide fusca, stromatibus 

 2 mm. lat. 1 mm. cras&is, scepe laviter collascentibus, intus 

 pallentibus vel albidis, pertheciis fuscis, ostiolis, vix prominulis 

 200 - 250 = 150 - 200, ascis linearibus breve pedicellatis 

 100 X 5, sp'>tidiis monostichis 8, e cellulis duabus incequalibus 

 mox decedentibus compositis, cellula superiori globosa 4- diam., 

 cellula inferiori cuboidea oblonga 6 x -4, fumose-olivaceis, conidiis. 

 Verticillium sacchari. 



In Fig. 72 is shown (after Went) an ascus of the Hypocraaa, 

 * ' containing eight spores. Latterly the idea seems to be taking 



hold that Sereh was the manifestation of peculiar soil and cultural conditions, 

 the various micro-organisms associated with it only becoming prominent 

 after the health of the cane had become affected. 



A point of great interest with this disease is the difference of opinion a& 

 to its infective nature ; the disease certainly spread from district to district in 

 Java, but conversely healthy sticks planted in an affected field remained 

 healthy. Whether infectious or not, the disease was found to be hereditary : 

 that is to say, canes planted from sound healthy seed gave healthy canes, but 

 tops derived from sereh struck canes became equally infected. 



146 



