INSTITUTE, PUSA, FOR 1918-19 79 



(7) Sugarcane smut. Mr. Dastur has investigated the 

 mode of infection of the sugarcane smut, Ustilago Sacchari 

 Rabenh. It has been found that direct infection of thin 

 varieties of cane can take place only in two ways : (1) 

 through the young tender " eyes " and (2) through the older 



' eyes '' when they are wounded or injured. Thick cane 

 varieties can only be infected in the latter manner, and this 

 is evidently one of the causes of their relative immunity to 

 smut. The infection has not been found to take place 

 through the cut ends of setts or through adventitious roots. 

 The hyphae enter the " eyes " through the unthickened scale 

 hairs, and have not been observed to penetrate the epider- 

 mal cells directly. Inoculated plants have given smutted 

 shoots in two months, while setts cut from canes, the dor- 

 mant eyes of which were infected in the autumn, gave rise 

 to smutted stools when sown the following spring. This 

 explains why setts taken from stools which show no exter- 

 nal signs of the disease can, when planted, give a smutted 

 crop. Further work is in progress but the results already 

 obtained mark a decided advance in our knowledge of the 

 aetiology of this important disease. 



(8) Rangoon bean. The disease of the Rangoon bean 

 (Phaseolus lunatus) originally erroneously reported in the 

 press as due to Phytophthora was investigated by Dr. Shaw 

 during the past year. The attention of the Department of 

 Agriculture, Burma, was first drawn to this disease by a 

 European planter engaged in agriculture in the Kyaukse 

 District. It is not improbable that the disease is of long 

 standing as even now Burmese cultivators are reluctant to 

 report its presence and may have had it for years without 

 the local agricultural authorities knowing of it. The recent 

 increase in the area under Rangoon bean (" pebyugale ") 

 and the method of cultivation which is practised, may have 

 increased the amount of the disease, but there is no means of 

 judging of the extent of the trouble prior to the first report. 



The increase in the area under Rangoon bean, conse- 

 quent upon the rise in price of this commodity during the 

 war, led to the crop being grown in situations in which it 



