E. J. BUTLER 5 



a mass of evidence to show that practically all the new fungal diseases of plants 

 that have appeared in Europe and the United States of recent years are 

 importations. The increasing intercourse with distant parts of the world 

 and the constant shortening of voyages have been the chief factors in dis- 

 seminating disease. The organism that causes ufra is subject to much 

 the same limitations of extension as fungi ; and it is far from unlikely that it 

 will be discovered in some of the countries with which India is in communica- 

 tion by sea and where the diseases of crops have not yet been investigated. 



Incidence of ufra in different types of paddy. 



The many hundreds of varieties of paddy grown in Eastern Bengal may 

 be grouped into three main classes. The horo or spring paddy is sown in 

 November to January and harvested in April-May. The aus or autumn 

 paddy is sown between March and May and harvested between July and 

 September. The aman or winter paddy (the main crop) is sown at about the 

 same time as the aus but the harvest is in November-December. 



The aman is the chief crop, accounting for over two-thirds of the acreage 

 under rice. The number of its varieties is legion. In any given locality, 

 types will be found suitable for the different levels of land. These levels, 

 though slightly marked, are of the utmost significance in paddy cultivation. 

 The general fall of the land, as in most deltas in the making, is away from the 

 river channels, and the water in the small channels flows away from and not 

 towards the main streams. So also, at least in Noakhali, the land does not 

 slope towards the sea, the coastal belt being generally higher (and therefore 

 growing more transplanted paddy) than the parts lying more to the north. 

 Between the main river channels the surface sinks into basins, but little above 

 sea level. Numerous semi-permanent swamps or " chars " are formed, but the 

 deposition of enormous volumes of silt is constantly changing the outlines of 

 these, and the cultivated margins tend to increase. The deposition of silt 

 is not uniform, and further irregularities are caused by the varying courses of 

 currents during flood time. The hand of man accentuates these difterences 

 of level by terracing and embanking ; and a field six inches or a foot higher 

 than those around it will often grow a different variety of paddy. In general, 

 the lowest fields grow the worst kinds, and the cultivator naturally aims at 

 raising his land where he can. Three or more dift'erent levels, each with a 

 different paddy, will often be found in one holding. 



Nevertheless there are great tracts unsuited for any but the so-called 

 deep-water or long-stemmed kinds. In many places they form the greater 



