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to the coco-nut may favour the root disease by hindering free 

 root development. Excessive moisture and excessive drought 

 may be favouring conditions for the disease. The latter can- 

 not be remedied except by irrigation and does not appear to 

 be a factor of any importance in this disease. The former, 

 excessive moisture, is noticeable in many of the low-lying portions 

 of the estates. In these hollows, the soil is often of a clayey 

 nature — impervious to water — and, therefore, many of the air 

 spaces between the soil particles are replaced by water. The nor- 

 mal working and growth of the roots is interfered with and the 

 destruction of such roots by fungal mycelium may speedily 

 follow. The effects of excessive moisture can be lessened by 

 careful attention to drainage and to the mechanical condition of 

 the soil. 



The present system of cultivation of coco-nuts in Trinidad 

 could be improved, and the attention of all growers of coco-nuts 

 should be drawn to the progressive German colonists and to the 

 Americans in the Philippines, where modern orchard methods are 

 being successfully practised in the treatment of coco-nut estates, 

 as improved cultivation would tend to retard the spread of 

 disease. 



22. Although the complete life-history of the fungus and its 

 method of spread is not yet known with certainty, it would appear 

 that owing to its habit in penetrating and spreading in the living 

 tissues of the root of the host plant, cure is practically outside the 

 question where a large majority of the roots are permeated with 

 mycelium, and therefore it is probable that only the most drastic 

 measures are likely to provide permanent relief. 



It cannot be expected that the disease can be entirely eradicated, 

 but, by a method of what is known as " stamping out," the amount 

 of disease may materially be reduced and the fungus kept in 

 check. 



There are six principal ways in which we may hope to attack 

 this disease. They are : — 



(i) Destruction of all diseased material. 



(2) Isolation of diseased areas. 



(3) Resting of infected land before planting 'supplies'. 



(4) Spraying and application of chemicals. 



(5) Improved cultivation and drainage. 



(6) Searching for and propagating disease-resistant varieties. 



I. — DESTRUCTION OF ALL DISEASED MATERIAL. 



It has been observed that diseased petioles that have fallen to 

 to the ground often bear large numbers of spores. This would 

 indicate that the fungus in the petioles is capable of living upon 

 dead matter, i.e., it is saprophytic during some stages of its life- 

 history. Young supplies, planted on the place whence dead trees 

 have been removed have also been noticed to be affected and old 

 stumps that have been left standing have become permeated with 

 fungal mycelium. These instances show that there is sufficient 

 food in the form of decaying vegetable matter in old trees, etc., to 



