58 



THE COCO-NUT 



CHAP. 



In the complicated bud rot the first attack is made 

 by the Diplodia. Quoting Fredholm : 



The earliest sign of the disease is retarded growth of the 

 " set " fruit, soon followed by the dropping of immature nuts. 

 At the same time none or very scant new fruit is " set." Next, 

 some of the leaves, generally the lower, begin to droop and turn 

 yellow at the tips, which yellowing progresses until the whole 

 leaf is involved. About the same time that the leaves become 

 discoloured the basal portion of the petioles commences to 

 show a dark-brown discoloration. Shortly the leaves dry and 

 are found hanging down along the trunk, finally falling either 

 as a whole at one time, but not infrequently breaking and 

 coming down piecemeal. Thus leaf after leaf withers, until all 

 are hanging from the " crown." But long before all the leaves 

 have dried, or even become yellow, the last leaf just emerging 

 from the top of the " crown," and as yet unexpanded, will be 

 seen to shrivel and die. 



The pustules already described in connection with 

 the Diplodia disease can be found on the bases of the 

 petioles. The death of the tree is to be expected three 

 months after the first symptoms are observed. 



If the crown of an infected tree is split, the usual 

 decay of the cabbage will be encountered. Unless 

 putrefaction is too advanced, the sides and top of the 

 decaying region will be found bordered with a reddish 

 tissue. 



Not seldom similarly discoloured areas will be found at the 

 base of a pedicel or a petiole below and at some distance from 

 the cavity and unconnected with it. Such conditions, when 

 met with, serve to illustrate matters of great importance, as 

 will be perceived when the mode of introduction of the 

 disease is studied. This discoloured material, if examined 

 microscopically, is found to consist of cell-tissues undergoing 

 destruction by the mycelium of a fungus. If the petiole is 

 split open its tissues will also be seen to be discoloured and 

 permeated by strands of mycelium. 



The disease is endemic . . . and is not infrequently met 

 with in the high woods. It is highly infectious, and after gain- 

 ing a foothold in a plantation it speedily becomes epidemic. 



Evidences point to the wind as the main factor in the 

 distribution. The disease is seen to progress more rapidly in 



