396 Howard. — On some Diseases of the 
the white mycelium, and that the majority of the roots are 
destroyed as before. It sometimes happens that these shoots 
die off, when they are found to be penetrated by this mycelium 
in all directions. 
The below-ground portions of the older shoots sometimes 
contain this mycelium and show reddening and extensive 
gumming of the vascular bundles. As the reaping-period 
approaches and the supply of water in the soil falls off, large 
cavities are formed in the centre of the internodes, in which, in 
cases where the canes are drying up, the white mycelium luxu- 
riates. In a short time such dying canes become infected 
by the saprophytic fungus Melanconium referred to above. 
The dark- coloured, elliptical areas on the living leaf- 
sheaths of many of the canes attacked by this disease were 
found to be due to the conidiophores and conidia of the 
fungus Cercospora vaginae , Kruger, which is described and 
figured by Wakker (14) and also by Kruger (15). As in 
Java, this parasite is extremely common in the West Indies 
on the leaf-sheaths of the sugar-cane, and is to be met with 
on both vigorous looking and obviously diseased canes. As 
it spreads from the older to the younger leaf-sheaths, when 
these are in contact, with the greatest ease, canes once infected 
are never able to get rid of this parasite. As the upper 
portions of the cane embracing the main growing-point 
(‘ tops ’) are generally used as plant-material, and as the 
leaf-sheaths adhering to the cuttings are often covered with 
this fungus, it is easy to understand that the young shoots 
become infected and that this disease is reproduced in every 
new stand of canes. By following the young shoots arising 
from the cuttings it can be readily seen that reinfection takes 
place almost before the young stems are above the ground, 
and that as far as this disease is concerned, parasite and host 
are planted together. 
The hard, spherical, yellowish, pea-like bodies noted on 
the leaf-sheaths of some of the diseased canes were found 
to be sclerotia. Identical structures, accompanied by redden- 
ing of the leaf-sheaths and sliminess on the inner side thereof 
