CHAPTER XVIII 



DISEASES OF COCONUT 



The Red Ring Disease 



The disease for which the above name is now used was first 

 brought to notice by J. H. Hart, in 1905, as occurring in the 

 district of Cedros on the west coast of Trinidad, where it had 

 apparently been in existence for many years. The disease was 

 investigated in Trinidad by F. A. Stockdale, in 1906, and dis- 

 tinguished, under the name of root disease, from the specific 

 bud-rot which it resembles in its later stages. It was attributed 

 by him to a fungus of the genus Botryodiplodia. J. B. Rorer 

 about 1910 made an extensive mycological investigation of 

 material from diseased trees, and reached the conclusion that the 

 affection was not due to any fungus parasite but that it was a 

 physiological trouble resulting from unfavourable conditions in 

 the soil. 



The present writer first met with the disease in Grenada in 

 1918, and finding a nematode to be constantly present in the 

 affected tissues put forward the theory that it was due to the 

 parasitism of this worm. This was supported by later observa- 

 tions in widely scattered localities in Trinidad, Tobago and 

 Grenada, and has been confirmed by numerous experiments in 

 which the introduction of small pieces of nematode-infested 

 tissue among the leaves of healthy trees has invariably led to their 

 rapid infestation with the worm and the reproduction of the 

 characteristic symptoms of the disease. 



The disease is widely prevalent in Trinidad and Tobago, and 

 has occurred in the last few years in various districts of Grenada. 

 Several cases are now known to have been met with in St. Vincent 

 about the year 1912 and a recent occurrence is reported. In 

 1920, W. R. Dunlop found the disease to be very prevalent in 

 the inland plantations of British Honduras, causing losses which 

 appear to be on as wide a scale as those in Trinidad. F. Stell 

 has found typical cases in British Guiana, and J. R. Johnston 

 reports its presence to a serious extent in Panama. There can 

 be little doubt, from various accounts seen of the losses of young 

 trees attributed to bud-rot, that the definitive description of 

 red ring disease will lead to its detection in several other localities 

 in tropical America. The writer has seen typical specimens 

 from Panama and Venezuela. 



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