584 Went.— Notes on Sugar-cane Diseases. 
leaves die : but as soon as the stems are split longitudinally, 
red spots are to be seen on the section. These spots are 
purple, but the colour is not equally distributed, it being 
darker in one place than in another. Very characteristic of 
this disease are white blotches in the interior of the red spots, 
these white blotches extending mostly in a direction transverse 
to the stalk. Another peculiarity is only to be seen on 
transverse sections, namely, that in the direction of the peri- 
phery the distinction between the dark red diseased tissue 
and the sound portion of the stem is very sharply defined. 
The periphery of the stem is generally not attacked ; this 
explains the fact that the symptoms of the disease are not 
seen externally, because the vascular bundles communicating 
with the leaves at the top are not affected. These red spots 
are to be found either in the middle of a joint or near the 
node ; but in either case careful examination is sure to show 
that the cane has been damaged in these places, either by 
some insect, like the moth-borer, or by some fungus-disease. 
Badly diseased canes are often red- spotted in the interior 
from the base to the top ; sometimes brownish spots may 
be seen at the nodes. 
With regard to the macroscopic characteristics of the 
disease, there only remains to be said that vascular bundles 
emerging from the diseased spots are red-coloured and gummy 
along a certain distance from the diseased place. I may here 
take the opportunity to state that wherever a part of the 
stem of a sugar-cane has been damaged, either by man or by 
animal or vegetable parasites, the vascular bundles commu- 
nicating with the damaged spot become gummy and red- 
coloured. This is not only the case in Java, but from the 
diseased canes received from Mr. Barber I was able to con- 
clude that sugar-cane in the West Indies behaves in exactly 
the same manner. A description of these gumming vascular 
bundles has been given by Valeton 1 . I would here repeat 
the statement that Bacteria have nothing to do with this 
1 Th. Valeton, Bijdrage tot de Kennis der Serehziekte : Mededeelingen van het 
Proefstation Oost-Java, 1891. 
