epidemic, that occurred in the British West Indies in 1893-7. It 

 is very easy to find a great variety of fungi but none of them have 

 as yet been capable of reproducing mottling. 



The connection of root disease has been a more difficult problem, 

 but it has finally become clear that root disease is not directly con- 

 nected with the mottling. Either, may and does occur alone, and 

 both are often found acting together, the cane suffering severely in 

 any case. 



The more the disease is studied the more it appears to resemble 

 the mj^sterious "sereh" of Java. It is quite unlikely that it is that 

 exact disease, but it is not improbable that it is of the same general 

 nature, produced by the same or similar environmental factors. Many 

 of the symptoms are the same, although none it must be admitted 

 are those that are considered essential ; for instance the course of 

 the disease over three j'ears, the stunting of stools and shortening of 

 internodes (in advance cases), the fact that the disease is carried 

 from old plants to new ones by cuttings, and a poor development 

 of the root system. On the other hand this new disease in addition 

 to the leaf mottling and stalk cankers not ascribed to "sereh," does 

 not show gumming, internal red lines, more disease at the base of 

 the stalls, or the abnormal stooling giving the grassj- appearance 

 from which the "sereh" takes its name. 



Control. — Practically every conceivable measure which has ever 

 been recommended for the control of cane diseases and especially 

 those usually given as efficacious for root disease have been tried, 

 and without any otlier result than the continued progress of the 

 disease. Liming, increased cultivation, treatment with Bordeaux mix- 

 ture, seed of estalilished varieties brought from outside regions, seed 

 of new varieties, and the use of land not before planted to cane, all 

 these, and more have been tried. 



It is apparent that very drastic measures will be necessary to 

 check the epidemic. The foremost requirement will be the introduc- 

 tion of a rotation system, (a heretofore unknown practice in Porto 

 Rican cane culture), and one which will include a legume. It is no 

 easy matter to give a satisfactory outline for such a rotation, particu- 

 larly tlie legume, and even after by such experimentation such is 

 found, it is going to be e(|ually or more difficult to get it adopted. 

 In the meanwhile continued efforts are being made with new seedling 

 varieties, particularly those produced at this Station, and it is hoped 

 that some will ultimately be found wliicli under proper care will 

 succeed. 



A complete account of the disease to date together with such 



232 



