DISEASES OF SUGAR CANE 301 



in their case should have coincided with a similar process in the 

 Bourbon, so that all became susceptible at the same time to a 

 fungus previously present, but there is a possibility, on the other 

 side of the argument, that mass exposure to the fungus de- 

 veloped on the Bourbon may have led to their infestation, as is 

 recorded of the Ribbon cane first adopted as a substitute in 

 Martinique. 



The third theory, of introduction from without, involves the 

 fewest difficulties and is supported by many analogous cases. 

 The records of the time show that there was an active exchange 

 of varieties between neighbouring and in some cases distant 

 countries. The Queen cane, for example, was brought from New 

 Caledonia to Trinidad in 1874, and sent from Trinidad to Jamaica, 

 whence it was introduced into St. Kitts in 1888 and passed 

 into cultivation in one district. It was brought to Barbados 

 from St. Kitts some years previous to 1893. This cane is recorded 

 to have proved highly resistant but not immune. That in some 

 such way as this Colletotrichum falcatum was introduced from the 

 East and distributed on the original or other varieties to the 

 various Botanic Stations is by far the most likely theory of a 

 matter that will probably never be conclusively settled. 



The objection that the attack was almost simultaneous through- 

 out the Lesser Antilles affects all the explanations alike, and is to 

 some extent lessened by the consideration that the attention 

 drawn to the disease in one island led to its recognition in another. 

 The more remote localities in the larger area of Trinidad were 

 much later in becoming infested, and, as mentioned above, 

 some continue at least relatively free to the present time. The 

 outbreak in British Guiana was also distinctly delayed. 



Red-Rot. 



The disease of sugar-cane caused by Colletotrichum falcatum 

 Went was first described by Went in Java in 1893, under the 

 Dutch name " het rood snot " — the red smut. The adoption of 

 red-rot as its name in English requires that care be taken not to 

 confuse it with " het rood rot " of Wakker and Went, which is a 

 sclerotium disease. 



Red-rot is the most serious disease of sugar-cane in India, 

 and is widely, probably universally, distributed through the 

 tropics. Its epidemic appearance as the cause of " rind disease " 

 in the West Indies about 1890 has been described above. Owing 

 to the general adoption of resistant varieties its interest at the 

 present time in these islands is mainly historical, but it can 

 sometimes be found by a careful search among seedling varieties, 

 and still occurs in quantity when the Bourbon cane is re-intro- 

 duced. 



