BUTLER AND HAFIZ. 163 



crop was suffering more or less severely from red rot and liave not 

 been able to satisfy ourselves in any case that the disease had 

 originated at the borer hole and not elsewhere. Yet we are 

 satisfied that there are other methods of infection than from below 

 ground and these may now be considered. 



Went and Howard both refer to infection through the scar 

 left when the leaf sheaths break away from the stem. In December, 

 1907, 20 Red Mauritius canes, almost fully grown, were inoculated 

 at the scar left by pulling off a leaf about the centre of the stem. 

 The leaves were old and came away readily. The inoculated 

 portion was kept moist for about 24 hours by covering with moist 

 sterile cotton wool. After three months the canes were examined. 

 One was damaged by a jackal and was discarded. In 3, acervuli 

 with spores of CoUetotrichum. falcatum were found on the surface of 

 the scar. In 11, there was no reddening of tlie tissues and no sign 

 of penetration. In 5, there was slight reddening at or near the node. 

 No hyphse, however, could be found and on incubating slabs, cut 

 so as to include the reddened parts, no CoUetotrichum developed. 

 Even in the 3 cases where the fungus had fructified on the spot, 

 no penetration occurred. 



At the cane node there are two other points of discontinuitv 

 in the rind, where the shoot bud (the " eye '') comes through 

 and where the eyes of the adventitious roots occur. These were 

 found to admit the fungus readily. In April, 1912, 12 buds of 

 Samsara cane were injured by rubbing with the fingers and 

 inoculated with spores and mycelium kept moist ])y cotton wool 

 as before. One was examined after three days and the hyphae wei-e 

 foimd to have penetrated the bud and to be growing vigorously. 

 After eleven days another was examined. The myceUum was still 

 confined to the bud, which was -nmch reddened. A week later 

 the rest were examined. All had taken the infection well and 

 in several the] hyphae had already entered the main stem. Injuiy 

 to the eye' buds, especially as the cane approaches maturit}', 

 is unfortunately oidy too comuion, and the fungus can readily 

 penetrate if such buds become contaminate<l. The uninjured 



