17G RED ROT OF SUGARCANE:. 



ceptible to iiifection fioiu aerial spores, wliicli were formed in con- 

 siderable quantity on the leaves during the outbreak at Pusa. T\\v 

 other case was a severe attack of red rot following extensive flooding 

 of the cane fields, in some estates in Bihar several years ago. The 

 effect of unfavourable external coiiditions such as this on the onset 

 of the disease is discussed more fully l)elow. 



Susceptibility of varieties of cane. 



Little ligiit has been thrown by these investigations on the 

 question of the relative susceptibility of different varieties of cane 

 to red rot. One fact that is obvious to any observer of the disease 

 in India is that the tliin varieties of cane are, on the whole, less sus- 

 ceptible than tiie tliick. 8onu^ of the Indian thin canes are so 

 widely divergent from the thick laces, that writers in Java have 

 suggested that they may have originated from different s])ecies of 

 SaccharHUL^ Jf so, one may perhaps anticipate lliat the relative 

 immunity of the tliiii kinds will prove to be a deep seated "' gei'm '" 

 character. With ix'gard to the thick canes, certain observers, 

 and in particular J)r. C. A. I>ail)er, hold that the temporary or 

 apparent inununity of c(Mtain thick varieties can be broken (h)wn 

 by bad cultivation, lie describes" how, in the (lodavaii Delta, 

 successive canes have held favour during the past forty years, each 

 in tuiii growing luxuriantly and bringing wealth, but after a few 

 vears becoming diseased. The constitution of each cane had beeji 

 broken in turn by the ever-present fungus, until all the plants of that 

 kind in the district were infected. Again he states^ that of th(^ 

 varieties of cane brought fiom other countries for tiial at Samalkota. 

 noJie wei'e really immune and it is probable that ultimately all will 

 succumb ill turn when plac('<l under the adverse conditions of the 

 local agriculture. In the same paj)er' he mentions as a curious fact 

 that the Hospet cane varies greatly in its liability to disease in the 

 diifeient regions where it is found. A similar case occurred with the 



' Kobus, J. D. Ovcrzicht van het vcrloop (Icr imi)ortafioplanncn van vrcenulc rictsoortcn 

 op een cilanil buiten Java. Arehiof v. d. .lava-Suikerindiistno, II, 1804, ]>. ()62. 



* Barber, C. A. The Samalkota Simarranc Farm. Auric, .lonni. of India T, 10(M). p. 45. 

 8 lb. Seedling canes in India. .Ainif. Joiirn. of IndJM, \'ll, 1!)I2. p. .S24. 



* lb. loc. cit. p. 329. 



