121 



Numerous instances have been seen where diseased trees just 

 coming into bearing have succumbed, and signs of old stumps 

 surrounding them have been noticed. These examples would 

 bear out the opinion of Mr. Hart that the disease has been present 

 in the colony for a considerable time. 



It is only recently that it has assumed dangerous proportions. 

 On one estate alone in the Cedros district, out of a total of 25,000 

 trees, 3,000 have been cut down within the last twelve months 

 and many more are either dead or in a diseased condition, and in 

 many other places the disease is already a serious annoyance. 



There is undoubtedly clanger of further spread. This danger 

 is emphasized by the recent rapid spread through some estates in 

 the Cedros district and if conditions favour its development and 

 proper remedial measures are not taken to check it, the coco-nut 

 industry of Trinidad will materially suffer 



Already some of the smaller proprietors are beginning to feel 

 the loss of returns and this loss will be felt the more severely if 

 the present prices for coco-nuts and their products do not hold. 



21. Samples of soil from around the roots of diseased trees 

 have been investigated microscopically, and sterile mycelium, 

 which appeared to agree with that found inside diseased roots, 

 was present in them. This would suggest that the mycelium is 

 capable of spreading through the soil. This mycelium may be 

 capable of attacking and killing the younger rootlets and then 

 entering into the larger ones. The entry of the mycelium into 

 the roots is still an unsolved problem, but evidence tends to show 

 that the larger roots first show signs of infection where the 

 smaller rootlets join them. In no case has the mycelium been 

 noticed on the exterior of the roots and it would seem that it has 

 to depend upon the rot of the smaller roots for its distribution. 



The roots of several young supplies, that were planted upon or 

 near to the place where diseased trees have been removed, showed 

 on examination, the presence of a mycelium within them but not 

 in sufficient quantities to cause their death. This indicates that 

 infection can take place through mycelium. 



It would appear to be probable that the disease may spread : — 

 (1.) By mycelium through the soil from root to root. 

 (I.) By spores blown from tree to tree. 



(3-) By germinating tubes of spores from petioles attacking 

 either the roots of the same tree or the roots of another. 

 (4.) By germinating " chlamydospores" from decaying 

 petioles. 



The best conditions for the germination of the spores depend 

 upon the presence of suitable quantities of air and moisture, 

 and the spread of the disease would be expected to be most rapid 

 when the conditions are the most favourable. The distribution 

 of fungus spores by wind and rain will be dealt with more fully 

 under the leaf disease and, therefore, will not be discussed 

 here. 



The spread of mycelium in the soil depends a good deal upon 

 the cultivation. Any condition of the soil that is unfavourable 



