THE PESTS AND DISEASES OF THE CANE. 



Sereh.. This disease was first recognised as such in 1882 in Java 

 where it has done very great harm. In the typical form of ' sereh ' 

 the stool of cane consists of a number of short stalks with very short 

 joints ; the buds, especially those below, sprout, whereby results a bundle of 

 short stems hidden in a mass of leaves. The whole stool bears a resemblance 

 to lemon grass (Andropogon schoenanthus] the Javanese term for which is 

 ' sereh? In a second type one or two stalks may grow to a fair size with very 

 short joints in the upper part; above all is a fan-shaped leaf crown; many of 

 the eyes, especially those below, sprout and form small branches. Benecke 39 

 has given the following symptoms of this disease : 



1. A low, shrubby growth, often only from 3-4 decimetres. 



2. A fan-shaped arrangement of the leaves arising from a shortening 



of the internodes. 



3. The internodes are only from ^ to f inch long. 



4. The nodes are tinted red. 



5. Numerous aerial roots are formed. 



6. The fibro vascular bundles are tinted red. 



7. Subterraneous outbranchings form. 



8. The sheath and root buds turn vermilion. 



9. In some cases there is no formation of wax on the stem. 



10. The growing part of the stalk is frequently dyed red. 



11. The leaf-sheath and the stalk stick together. 



12. There is an accumulation of secondary organisms. 



The presence of gum in * sereh ' cane is a point about which much has 

 been written ; the major portion of opinion seems to be that the presence of 

 gum is a consequence of, and not directly connected with, the disease ; if the 

 gum is of bacterial origin the growth of the bacteria might only take place in 

 canes already weakened by disease. 



A red colouration of the fibrovascular bundles is a characteristic of 

 1 sereh ' ; this colouration is most pronounced in the node, but often appears in 

 the internode in the form of a red stripe ; this appearance is quite distinct 

 from the red patch with white centre characteristic of the l red rot of the 

 stem. 1 



A red string of the sugar cane associated with the presence of gum has 

 also been described by Grieg Smith 40 ; this he ascribes to the association of an 

 unidentified ascomycete with a slime producing bacillus, which he names 

 JB. pseudarabinus. 



The immense amount of work that has been done on Sereh has quite 

 failed to elucidate the cause of the disease ; opinion is divided in ascribing the 

 cause to physiological and to pathological influences ; amongst the first, bad 

 drainage, injudicious manuring, late planting, excessive ratoonage, an 

 insufficiency of silica in the soil, and degenerescence have been suggested. 



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