DISEASES AND PESTS 39 



generally an intense greenish brown. . . . After a time, when 

 a large number of disease spots have made their appearance, 

 the whole leaf assumes a yellowish appearance, and gradually 

 becomes greyish and withered. . . . When a large number of 

 the leaves have been badly attacked the terminal bud is left 

 standing alone, and it is only a question of time before this 

 falls over, and the death of the palm results. . . . Close 

 examination of the upper surface of the leaf of one of the 

 disease spots when it has assumed the grey colour shows 

 minute warts not larger than the head of a small pin. They 

 are blackish-grey in colour, and are irregularly distributed, 

 often being very numerous. . . . These small pustules bear 

 the spores of the fungus. . . . The distribution of this fungus 

 appears to be fairly general in Trinidad, but it is a serious pest 

 in only two districts. 



Stockdale advises that all dead trees be cut down, 

 and all dead material burned. If a tree has but a few- 

 diseased leaves, these should be cut off and v burned, and 

 the tree watched for more. If a fungicide is tried, 

 Bordeaux mixture is recommended. 



Preuss reports Pestalozzia as doing serious mischief 

 to seedlings in the Bismarck Archipelago. 



Diplodia. — The exact botanical standing of the 

 fungi which cause the disease or diseases to be described 

 next is still in doubt. This is not a matter of merely 

 scientific interest, but one of very practical importance ; 

 for so long as we do not know just what organisms 

 cause each of the forms of disease in question, we are 

 not likely to know that the diseases of petioles and those 

 of roots are or are not identical, nor whether or not the 

 coco-nut and cacao harbour pests dangerous to each 

 other. Without such knowledge preventive measures , 

 must be taken partly in the dark, or else grave risks 

 be run. 



The following account of the Trinidad " root disease " 

 is extracted from the report of Stockdale, who regarded 

 it in 1906 as the most dangerous of the three diseases 

 he found on that island : 



An attack of this disease is generally first shown by the 

 leaves. They show a slightly wilted appearance, then turn 



