^86 NEW SUGARCANE DISEASES 



On the same day 1 5 canes were inoculated at leaf scars, the 

 scar being covered after inoculation with a wad of damp sterile 

 cotton-wool, bound with gutta-percha sheeting. The same 

 material was used as in the last experiment. 



These inoculations also succeeded, distinct reddened bundles 

 being found after 3 months, extending downward from the scar 

 through the next internode. The progress of the infection was 

 less than in the last case and could not be traced beyond the 

 one internode. The hyphse were found chiefly in the red- 

 dened bundles and there was not much lateral spread. It was 

 noticed that shoots arisino- from the inoculated nodes were not 

 infected. 



The fungus cannot penetrate the unbroken rind of the 

 internodes. Sixteen inoculations were made to test this, a drop 

 of the suspension being placed on the rind, and covered with 

 damp sterile cotton -wool for 48 hours. In no case was there 

 the slightest sign of infection. 



As in Colletotriclmm falcatum, however, the adventitious 

 root eyes at the nodes can be inoculated successfull}-. Ten 

 inoculations were made on the uninjured eyes, in exactly the 

 same way as in the last experiment, except that the cotton-wool 

 was removed after 3G hours. The first sio-n of success was 



o 



noticed after 4 days ; one of the eyes being slightly discoloured. 

 On sectioning, the hyphai were found to have penetrated through 

 the epidermis and to have reached almost to the centre of the 

 bud. Three days later all the inoculations had clearly succeeded, 

 the eyes being reddened and full of hyphcC. After 10 or 11 days 

 the eyes were quite killed and the hyphc\3 were passing into the 

 main stem. 



To see if the cane can be infected through the setts at the 

 time of planting, half a trench of Striped Mauritius was planted 

 on March 7th, 1907, after dipping the cut setts in a suspension 

 of spores and mycelium in distilled water. The remaining half 

 trench served as control. Germination was approximately equal in 

 the two halves, but 22 shoots withered in the inoculated half up 

 to June 17th, whereas there were only a few deaths in the other 



