DISEASES OF SUGAR CANE 323 



cushion on the under surface, and bear hyaline conidia with 5-7 

 cells, 



Sereh. 

 History. 



The Sereh disease caused in Java in the 'eighties of last 

 century a crisis comparable with the effects of the " rind disease " 

 epidemic in the West Indies. The disease received its name 

 from the resemblance of seriously affected plants to bunches of 

 lemon grass, the Javan name of which is Sereh. There is no 

 reason to believe that the affection occurs in the West Indies, 

 but as alarm concerning it has arisen from time to time, and 

 in view of the possibility of its future occurrence, a brief descrip- 

 tion based on Went's account of the disease in Java is here 

 supplied. 



In the first years following its discovery the Sereh disease 

 progressively extended over the greater part of the cane fields of 

 the country, with serious results. A re-organisation of the 

 industry on a scientific basis took place, and measures were 

 found and adopted which made evasion of the disease possible. 

 These are troublesome and expensive, but no direct remedy 

 has been found to take their place. 



Nature of the Attack. 



The outward signs of attack are seen in changes in the habit 

 of the plant, which may occur to very different degrees. 



In the worst cases the internodes are largely or entirely 

 suppressed, so that there are few stems of any length to be seen. 

 The leaves are small and expand prematurely, and being crowded 

 together in two ranks they give to the top of the shoot the 

 appearance of a fan. Abnormally large numbers of shoots are 

 produced from each stool. A thick network of roots develops 

 under the leaf -sheaths of those canes which possess a stem. 



In cases of less severity stems of normal length are produced, 

 but they develop fan-like tops and many of the buds upon their 

 sprout and form short side-shoots. As in the first type, roots 

 develop along the stem. In the third and least severe type there 

 is hardly any outward alteration beyond the formation of the 

 characteristic short joints at the top of the stems. 



An internal symptom which is common to all the types 

 consists in the discoloration of the vascular bundles entering the 

 stem from the leaf-sheaths, which are reddened for a longer or 

 shorter portion of their course and under the microscope are 

 found to contain a gummy substance. According to recent 

 findings by H.M. Quanjer, necrosis of the phloem strands in the 

 vascular bundles is a constant and fundamental character. 



Starting with sound canes planted in an infected area the 

 typical course of the disease on plant cane is that the first crop 



