INSTITUTE, PUSA, FOR 1916-17 5-5 



does not reproduce if immersed in water or if kept dry, 

 but only in moist air. There is therefore no multiplication 

 of the parasite in the flooded fields nor amongst any that 

 may get carried up on the growing boro plants. If the 

 plants are covered with bell jars, so that the air around 

 them is kept nearly saturated, infection can readily be ob- 

 tained from artificial inoculations at any time of the year. 

 If not covered, successful infections can only be got during 

 the rains and early cold weather, while the natural humi- 

 dity is high. 



The escape of the transplanted paddy is due to the fact 

 that it is grown on relatively high ground. The crop is 

 harvested so that not much stubble is left, and the fields are 

 ploughed early. It has been proved that worms set free 

 into the soil do not remain alive long, and the new crop is 

 not transplanted out until much after the period that has 

 proved sufficient to free the soil from infection. If worms 

 could reach the transplanted fields from neighbouring in- 

 fected broadcasted fields, they would doubtless attack the 

 transplanted paddy ; but as a rule the flood water does not 

 rise sufficiently to establish direct connection until rela- 

 tively late in the season, and often not at all. That infec- 

 tion in this way does, however, sometimes occur is probable 

 from the occasional reports that have been received of inj nry 

 to the trans]3lanted winter crop. 



In certain parts of the infected area, the rice bhils* are 

 narrow and deeply concave. In the bottom of these, the soil 

 remains muddy until February and, where deep-water 

 aman has been grown, a second growth of small shoots and 

 ears, arising from the long, matted stubble, can be found up 

 to mid-February. In infected bhils this second growth har- 

 bours large numbers of actively feeding and multiplying 

 worms. The ground does not dry out sufficiently to permit 

 of ploughing until February in many cases, and the new 

 crop has to be broadcasted very soon — in March — as the bh il 

 bottoms flood early. Hence the worms have only about a 

 month to live through before the new crop is sown and free 



*Ba sin-like depressions which always hold water in the rains. 



