E. J. BUTLER 35 



becomes dense at an early period, the air within the crop approaches saturation 

 sooner than elsewhere. It has been shown abovte that some worms can survive 

 total immersion for at least 5 weeks even in the cold weather and for nearly 

 2 months if kept warm, so that by May we should expect a certain amount of 

 active infection to be in progress in the crop. Probably the first infection is 

 slight but all the conditions thenceforward are suitable for multiplication and 

 migration. Thus we would expect to find the earlier attacks developing in 

 these low-lying patches and spreading to the surrounding paddy, and this is 

 exactly what the writer has been assured by cultivators in several places 

 actually occurs. It is not suggested that all or the majority of the attacks 

 originate from swampy patches. In the parts of Noakhali that the writer 

 has visited, for instance, the attacks occur scattered through the paddy flats 

 and often in different places in different years. But in the swampy, narrow, 

 and deeply concave bils of the Madhupur Jungle the cultivators say that 

 the infection often begins in the bottom patches year after year. 



There seem to be only two ways in which these swampy patches can be 

 dealt with, since there is little prospect of effectively burning the stubble in 

 them. One is by drainage, and the other is by transforming them into boro 

 paddy fields. 



If they can be drained so as to dry out soon after harvest, no second 

 growth is likely to come from the stubble and the latter can be removed and 

 burned much earlier than is practicable at present. Thus they will be brought 

 into conditions similar to those of fields where early burning and ploughing 

 have proved effective in checking ufra. 



The alternative is to deepen them so that they will hold standing water 

 in which boro can be grown. This means abandoning the growth of deep- 

 water aman in them, since aman cannot be grown after boro because the 

 harvest of the latter is too late to permit of broadcasting aman. But this is 

 no disadvantage, as boro is a more profitable crop than deep-water aman in 

 most places. The difficulty is the water-supply. Standing water must be 

 maintained in the boro fields until April, and this is only possible with irriga- 

 tion, which is usually given about once a fortnight. Hence boro can only be 

 grown, as already pointed out, along the banks of permanent channels, and 

 if there is none near at hand where it is proposed to make swamp aman into 

 boro land, one must be dug. The cost of this is considerable, but since these 

 channels are the main means of communication (roads being useless where the 

 country is submerged for half the year) the people are extraordinarily keen 

 on getting new ones cut. 



