F. J. F. SHAW. 13 



was obtained from localities as widely separate as Mandalay, 

 Samalkota and Pusa ; the external syniptoms of disease were 

 in all cases essentially the same. Infected plants can usually be 

 distinguished from their healthy neighbours by the phenomenon 

 of " tillering," that is to say, the development of fresh gr^en 

 shoots from adventitious buds at the base of the infected culm 

 (PI. I, Fig. 1). The infected culm gradually turns yellow and 

 dies ; any grain which it bears is light and poorly developed, in 

 fact, there is usually nothing within the glumes. The most dis- 

 tinctive feature, indeed, the easiest means of detecting infected 

 plants in the field, is the "tillering" from the base. In Pusa 

 the disease does not make its appearance until the paddy crop 

 is fairly well advanced ; hence, even supposing that the fresh 

 shoots remain free from the fungus, an unlikely event, there is no 

 possibility of their producing an}' grain. It is the loss of grain 

 which constitutes the most serious damao-e due to this funous. 

 In Burma the disease is one of the causes producing the condition 

 known as " gwa-bo " ; as, however, a number of insect diseases of 

 paddy are included under this name, it is difficult to ascertain 

 the precise amount of damage due to the fungus. The collec- 

 tive damage done by the combined insect and fungus attack is 

 stated to run into hundreds of lakhs of rupees annually. Miyake 

 in his description of the disease in Japan saj^s : " Durch diese 

 Parasitieruno- wird die Bilduno- der Reiskorner unvollstiindinor 

 daher ist der Schaden sehr-gross." He does not appear to have 

 observed the phenomenon of " tillering," a fact which Cattaneo 

 also overlooked. 



If a diseased culm is split longitudinally the basal portion is 

 found to be infested with the fungus. The hypha:" form a dark 

 greyish weft within the hollow stem, and small black sclerotia 

 can be seen dotted all over the inner surface (PI. II, Fig. 1 ). 

 Sometimes the base of the culm is quite free from the fungus and 

 the attack begins at a node some distance up the stem, A trans- 

 verse section through an infected culm shows that hyph« and 

 sclerotia are not only present on the inner surface of the stem, 

 but that the hyphcc penetrate the cells, and sclemtia are even 



