E. J. BUTLER 27 



perhaps a couple of months. The fields intended for transplanting are very 

 well prepared by ploughing in the spring as compared with those in which the 

 broadcasted varieties are grown ; being relatively high, they dry out early ; 

 and any stubble left is well ploughed in and soon decomposes. Where trans- 

 planted aman follows jute they are, in addition, usually flooded with at least 

 a few inches of water for a couple of months before transplanting is done. 

 This would be likely to finish off any worms that might have survived. But 

 as stated on pp. 7 and 8, there are certain cases in which transplanted aman is 

 reported to be attacked. The best authenticated are where the crop is trans- 

 planted in relatively low land, as in the areas in Feni where either transplanting 

 or broadcasting is done according to the season, and in those in Noakhali where 

 aman follows low-level aus. In the former case roacha is sometimes trans- 

 planted in land that is so low that transplanting has to be done into 18 inches 

 or so of water, special varieties that will stand this depth being used. Where 

 the former broadcasted crop was diseased, the transplanted is said also to get 

 attacked. In such low land it is probable that conditions are more like those 

 of the deep-water areas than the usual " sail " lands, and they probably do 

 not dry out sufficiently for cultivation until relatively late in the year. They 

 seem to differ but little from the conditions already known to lead to disease 

 in the broadcasted crop. Where aman is transplanted after broadcasted 

 early aus in Noakhali, the new crop is put in about a fortnight after the aus 

 harvest, into water that must contain free-swimming worms if the aus has 

 been diseased. The humidity conditions at the time are entirely suitable 

 for migration on to the new seedlings, and the latter cannot be expected to 

 escape. Except in such cases it is hard to see how ufra could be carried over 

 from one transplanted crop to the next, unless conveyed in the seed, and this 

 could only cause damage to the seed-bed, which is usually sown when the 

 humidity is too low to permit migration. 



The control of ufra. 



There is as yet no indication that any variety of paddy is naturally 

 resistant to the attacks of the rice worm. The number of distinct varieties 

 grown is enormous and probably only a small proportion of them has as yet 

 been exposed to infection, either natural or through artificial inoculation. 

 Still there has been no report that any of the numerous kinds of deep-water 

 aman grown within the limits of the infected tract can escape, the nearest 

 approach being some of the " digha " or " Aswina " varieties, which mature 

 early and so avoid attack to some extent. With these there is no question 

 of natural immunity, but they merely do not give sufficient time between 



