10 HISTORY Al^D CAUSE OP THE COCONUT BUD-ROT. 



certain specific bacteria, but methods by which it can be absolutely 

 controlled remain yet to be found. A thorough knowledge of the 

 conditions under which the disease occurs, including the difficulties 

 involved in carrying on an investigation of it, is so important that it 

 has been considered desirable to describe in some detail the work 

 carried out by the writer. The salient points brought out by the 

 observations of earlier investigators have also been included. 



NATURE OF THE DISEASE. 



General diagnosis. — The common name of the disease, bud-rot, 

 well describes its nature, for in its acute or advanced stages the bud 

 of the tree, i. e., the growing point in the center of the cro%vn, is 

 affected by a vile-smelling soft rot which destroys all the younger 

 tissues. At this stage most of the nuts have fallen, the lower leaves 

 are turning yellow, and the middle folded and undeveloped leaves 

 are dead and hang down between the still green surrounding leaves. 

 Signs of the disease in its incipiency are (1) the falling of the immature 

 nuts (PL I) ; (2) a staining of the opening flower spikes, partly or 

 wholly, to a rich chocolate brown (PL II, figs. 1 and 2; and PL III, 

 fig. 1) ; and (3) the dying and bending over of the middle undeveloped 

 leaves. Wlien the nuts are being shed investigation reveals at the 

 base of the affected spikes a dark-colored wet rot which spreads 

 around the leaf sheaths, or strainers, as they are locally known. This 

 rot appears as water-soaked areas which may reach a length of 15 or 

 20 centimeters on both the upper and lower surfaces of the bases of the 

 leaves (PL II, fig. 3 ; and PL III, figs. 2 and 3). This condition often 

 penetrates the leaf bases to a depth of 2 centimeters or more, and the 

 tissues involved in it swarm with bacteria. As the white tissues at the 

 base of the leaf become old and green the water-soaked spots harden, 

 and they may often be found in this condition on otherwise perfectly 

 healthy trees. 



The rot gradually spreads from the base of one spike to another 

 through the wet strainer. It is probable that insects carry the dis- 

 ease from one part to another, since there may be one or more 

 points of infection. Gradually all the spikes become affected and 

 shed their nuts, and the leafstalks become so rotted at their bases that 

 they are not able to maintain their natural position, but are pendent 

 (PL IV), often for a long time, or else fall off. 



If the infection starts in the central leaves the disease is apt to 

 progress rapidly downward into the younger tissues, which it is very 

 active in disintegrating, the vascular bundles being so soft as to allow 

 the tissues to go entirely to pieces. In the center it may progress into 

 the trunk for a short distance and rot out the fundamental tissue, 



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