2 THE RICE wor:m (tylenchus angustus) and its control 



are submerged with flood water from a few inches to 12 feet or more * in 

 depth. Traffic is confined to boats, except along a few high-roads. The 

 water faUs after the rains, and at the time when the disease is at its height even 

 boat traffic becomes difficult outside the main waterways. Ufra may 

 remain undetected unless the fields are actually waited, and this is not always 

 as easy as it appears. Where, as is often the case, the disease is not recognized 

 as such but attributed to thunder or other uncontrollable agencies, outside 

 assistance is not invoked. The cultivator considers himself unfortunate, but 

 it does not occur to him to report his misfortune to the authorities. The 

 agricultural staff, ridiculously small for the area, may be long before it learns 

 that anything is wrong. Thus there are large tracts in Faridpur and Backer- 

 gunge where much damage has been done for the past 10 years but which were 

 only discovered in 1916. When boat traffic is easy, ufra is in its earliest 

 stage in the winter crop and hard to detect ; when, on the other hand, the 

 ground is dry enough for walking, the harvest is over. In certain places it 

 has been noticeable that the reports of damage observed by the staff employed 

 in surveying the infected districts are chiefly from the vicinity of waterways 

 that are practicable in November, the season when the disease is most easily 

 recognized : the hitherto recorded outbreaks in Faridpur and Backergunge 

 are confined to the neighborhood of large " chars," or swamps that hold 

 water well into the cold weather. It is highly probable that such cases do not 

 entirely represent the truth, that the large areas which are difficult to reach 

 as the paddy ripens, owing to the fall of the water, are equalh^ ravaged by 

 the disease. In further support of this view is the fact that in the Dacca 

 District the villages from which ufra has been reported are mostly acces- 

 sible in the rains from the high land that extends north of Dacca town towards 

 the Madhupur Jungle, or from the navigable waterways. No report was 

 obtained from the Manikganj Subdivision, less easy of access, until a special 

 search was made in 1917, when it was found heavily infected. 



Hence it is quite impossible as yet to form an accurate estimate of the 

 extent of the infected tract or of the amount of damage caused by the disease. 

 The accompanying map gives roughly the limits of the disease as at present 

 known. 



The southern limits of the infected area were accurately defined east of 

 the Meghna, in August, 1917. They are, from east to west, the villages near 

 Dhoom just south of the Mahari and Bara Feni rivers (as hich have been crossed 



* I have seen a fair crop of paddy in a ficlfl where the measured depth of water 

 exceeded 12 feet. 



