occasion to visit diseased elds, is the peculiar mottling" of the leaves. 

 In contrast to the uniform yellowing or whitening of the leaves 

 characteristic of chlorosis, there occnr innumerable white or at times 

 yellowish spots and stripes with irregular, indefinite margins. In 

 light cases the back ground may be practically normal green, but 

 more often and especially after the first year the leaves are yellow 

 green to yellow, interspersed with the white markings. It is not 

 apparent that mottled leaves die any sooner, or are more subject to 

 parasitic leaf fungi than normal leaves. 



For some time there are no further symptoms than the mottling 

 it being impossible to distinguish, except for this one point, diseased 

 from normal stools. ^lottled leaves do not die and fall any sooner 

 than normal ones, nor do they cling abnormally to the stalk. The 

 stalks are not stunted or visibly changed internally. It is cjuite pos- 

 sible to find stalks which show from one to ten or twelve lower leaves 

 apparently normal, with all those above mottled. The mottling is 

 apparent as soon as the leaves iinfold. The reverse condition of 

 normal leaves above, has not been observed. It is not certain yet 

 as to whether a leaf which unfolds normally may become mottled later 

 on. A varying number of stalks in a stool may show mottling, often 

 only one, more often three or four out of a dozen. 



The above represents conditions the first year of infection. The 

 ratoon shoots from all infected stools, and from a varying propor- 

 tion of those that were apparently normal, show mottling from the 

 instant the new shoots are observable. Very seldom does this crop 

 reach normal conditions of height and stand, more often around 

 thirty to fiftj' per cent only. 



At this stage in addition to the mottling another marked charac- 

 teristic appears, a cankering of the stalks. These cankers or lesions 

 appear first as far as observation show, before the leaf sheaths fall, 

 but after they have become somewhat loosened, as linear spots, some- 

 what sunken, and brown in color. The soon become ashen or dull 

 gray, and often coalesce to form continuous patches practically cov- 

 ering the internodes. They never, however, pass from one internode 

 to another. They are superficial only, never penetrating for more 

 than 1-2 mm., except along such cracks as occur. Even here the 

 reddening that is found is seldom more than that usually found in 

 such locations in normal cane. 



The cracking or splitting is not considered a symptom, being 

 merely a result of the drying up of the cane. Splitting normally 

 occurs in many varieties, although of course it is more marked wnth 

 this disease. There is no internal red-rot or other form of rot accom- 



230 



