i84 DISEASES OF CROP-PLANTS 



in any case the effects of bacterial invasion are prominent in the 

 affected tissues from an early stage. 



Bacterial Bud-Rot. 



The early history of bud-rot disease in the Western Tropics 

 is obscure owing to the absence of adequate descriptions and the 

 difficulties of diagnosis. There is a record of epidemic des- 

 truction of coconut trees on Grand Cayman as early as 1834 > 

 in Cuba the disease has been making progress for more than 

 thirty years, and there are large areas once covered with flourish- 

 ing plantations on which hardly a tree now remains. Heavy 

 losses occurred in Jamaica from 1891 to 1910, and at about 

 the same period in Trinidad, and though checked by compulsory 

 destruction of trees the disease still persists in both islands. 

 In the Lesser Antilles small groups of trees have died from time 

 to time with symptoms taken to be evidence of this disease. 



Many incomplete attempts at explanation of the disease 

 were made from time to time. In some cases observers were led 

 by the presence of insects attracted by the decaying parts to 

 attribute to one or another of them its causation, but several 

 of the earlier observers reached the conclusion that bacteria 

 play the princif)al part. As a sequel to a visit by E. F. Smith 

 to Cuba in 1904, J. R. Johnston began the study of the disease 

 in Cuba in 1907, and after visiting Jamaica, Trinidad and British 

 Guiana, wrote a comprehensive account of his investigations. 



J. B. Rorer in Trinidad, and S. F. Ashby in Jamaica, have also 

 published descriptions of the disease confirming the general 

 features of Johnston's account. 



Nature of the Attack. 



The disease does not affect the central bud alone but may 

 commence anywhere in the crown, either at the base of the 

 leaves or inflorescences or on the tissues between them. It 

 never extends far on to the leaf stalk nor does it affect the woody 

 part of the stem ; only in exceptional cases does it travel more 

 than a foot or two in the softer central portion of the stem 

 below the crown. 



If the infection starts in or near the central bud it rots the 

 tissues at the base of the upright column of unexpanded leaves 

 so that this falls over and comes away, commonly leaving the 

 expanded leaves still green and healthy and their bunches of 

 nuts intact. With the only vegetative bud gone there is, of 

 course, no chance of recovery. The leaves in time dry up and 

 fall, leaving a bare pole. 



When infection begins among the expanded leaves the first 

 sign is commonly the falling of unripe nuts, due to the infection 

 of the base of the fruiting branch. The dropping of young nuts 

 is not in itself evidence of bud-rot. It occurs quite commonly 



