127 



The visual characters of the disease are subject to con- 

 siderable variation, but there is one character that is more or 

 less decisive, and that is the occurrence of a "pipe" through 

 the axis of the cane. This pipe is dark colored, in fact, is 

 sooty black when fuDy developed. I know of no other cause 

 for this peculiar appearance when it occurs in planted cane 

 cuttings. The rind-disease will discolor the interior of cut- 

 tings, and even render their tissues more or less black. But 

 these dark appearances are marginal rather than central, and are 

 seldom symmetrically arranged. Nor are they, as a rule, sooty 

 in appearance. We may assume then that any cutting that 

 has been planted for above a week and shows a central sooty- 

 black "pipe," is sufiferincr from pineapple disease, especially if 

 the odor of the more undeveloped part of the pipe is of the char- 

 acter described above; and if the odof is distinctly that of 

 pineapples, or thereabouts, there can be no doubt of the 

 identity of the disease. This makes it unnecessary in many 

 cases to resort to the microscope for a determination. 



The onset of the disease is at the end of the cutting, and it 

 proceeds toward the middle along- the axis of the cutting, 

 usually from both ends. It appears that the looser axial por- 

 tion of the cane stalk is that most suitable for the development 

 of the fungus, no doubt on account of the presence of air. Fin- 

 ally, of course, all parts of the cutting except the rind are 

 attacked. The softer varieties like Lahaina, Rose Bamboo 

 and Striped Singapore are reduced to a mass of black fibres 

 contained in a thin shell, for the rind resists decay much 

 longer than the center. If the variety has a thick and tough 

 rind the "pipe" is more pronounced and is confined more nearly 

 to the axial region. This is true of Yellow Caledonia. 



The disease is not known to have the power to enter the 

 sound tissues of cane or other plants. As it always enters 

 through some break or wound, it is ranked with the wound 

 parasites. So far as cane is concerned the "wound," in most 

 cases, is the cut surface of the cane, the disease beinsr larg^elv 

 confined to attacks on cuttings after they are planted. 



PROGRESS OF THE DISEASE. 



In its progress through the cutting the fungus has to pause 

 at. each node on account of the extra density of the nodal tissues. 

 After struggling through the node it again makes rapid progress 

 until it reaches the next node. The entrance to a new internode is 

 usually m.arked by the appearance of pink or red elongated streaks 

 in the central tissues of the cutting, and these colors may extend in 

 a modified degree to the marginal parts. It is during the accelera- 



