THE PESTS AND DISEASES OF THE CANE. 



disease, which at this time it is hopeless to attempt to identify, was 

 characterized by a ' cork-screwing' (tire-bouchonnage] of the top, a 'yellowing off ' 

 and drying up ; the authority quoted above states that it is on record that the 

 canes showed signs of degenerescence for fifteen years previous to the epidemic.* 

 About 1865, the Louzier cane (cf. Chapter IV.) originated per saltum in 

 Mauritius and there is evidence that this cane is the Otaheite, or staple cane of 

 these islands, previous to the epidemic of the forties ; for a generation this 

 cane remained the standard cane of Mauritius, and again in the nineties it 

 suffered from a maladie. This disease has been discussed above. Here then 

 exists a case of a cane twice forming the standard in a space of fifty years, 

 and twice being almost exterminated by disease ; in the second epidemic relief 

 was obtained by the planting of the Tanna canes. 



Other disease epidemics are known ; in Madeira and Natal the Uba cane 

 has replaced one which had become diseased ; in Australia the ' gumming ' 

 disease has assumed epidemic form ; the Rind fungus (the etiology of which 

 is still not altogether satisfactory) of the nineties in the West Indies, and the 

 Sereh disease of Java, so ably controlled by the plant-breeding work of Kobus 

 and others, are well known instances. Though these epidemics are due to 

 micro-organisms, yet the action of these is accentuated by, and perhaps may be 

 initially caused by, negligence of plant hygiene. Quite recently Harrison 56 has 

 struck a warning note when he writes: "I have personally never 

 favoured the readiness so apparent of late years to refer almost every 

 instance of decreased yield in cultivated plants to the noxious action 

 of microbes or fungi. It appears to me that for a long time back 

 we have in the tropics rather neglected what I may call the physical and 

 chemical hygiene of our cultivated soils, and have not paid sufficient attention 

 to the soil-conditions which may have materially reduced the naturally 



resistant powers of plants to the attacks of bacteria and fungi And 



further, I think that the susceptibility of certain kinds of plants, for instance, 

 the Bourbon cane, to injury by drought and fungus attacks is due in part at 

 least to the defective conditions of soil hygiene under which, in places, they are 

 now cultivated." 



REFERENCES IN CHAPTER IX. 



1. Das Zuclcerrohr. 



2. De dierlijke vijanden van het suikerriet. 



3. W. I. B., I., 327. 



4. Agric. Jour, of India, April, 1908. 



5. Agric. Gaz., N.S.W., 1893, 373. 



6. S. <?., 44-51. 



7. W. L ., IY., 37. 



8. H. P. M., Nov., 1900. 



9. Porto Rico Agric. Exp. St., Bull. 2. 



*May not this degenerescence have been due to the gradual infection of both seed and 

 soil due to the use of infected tops ? 



157 



