The area of cacao under cultivation in the tropics is, 

 comparatively speaking, large and continues to increase 

 from year to year ; this must eventually lead to very severe 

 competition, and those countries will hold their own which 

 have efficient methods of cultivation, good and cheap 

 labour, etc., which can produce the best varieties and last, 

 but by no means least, which are able to keep their pests 

 under control. It is, for this reason that the fungi parasitic 

 on cacao should demand the most careful attention of the 

 mycologist. 



Methods of Treatment. — Throughout the tropical world 

 it is gradually becoming more generally recognised that 

 careful treatment of plant diseases is necessary for the 

 successful cultivation of economic plants. As with the 

 study of human and animal pathology, so with plant 

 pathology, the practice resolves itself into the careful 

 observation of the causes and symptoms before the remedial 

 means can be suggested. For the successful treatment of 

 fungus disease a knowledge of the life-history of the fungus 

 causing the disease is of primary importance, in order to 

 know when to attack the fungus, how to diminish the 

 conditions which are most favourable to its development, 

 and what parts to destroy so as to prevent it from continuing 

 its existence in some future period. 



Those methods of treating fungus disease which are most 

 commonly practised may be summarised as follows : — 



i. The destruction of diseased material, which is best 

 effected by burning the diseased parts or by burying them 

 in pits, with or without the addition of lime, should always 

 be practised ; it resolves itself into the diminution of the 

 number of spores by which the fungus reproduces itself. 

 In some cases it is necessary to destroy the whole plant, 

 in others only certain parts of the plant need be destroyed. 

 Diseased material should never be thrown on the manure 

 heap ; if this is done a recurrence of the disease is 

 secured. 



ii. Parts taken from diseased plants should never be 

 used for propagation. Cuttings, bulbs, seeds and tubers 

 produced by diseased plants, if planted, only serve 

 to perpetuate the disease. The disease caused by 

 TrichospJiaeria Sacchari was widely spread by the use of 

 cuttings which were taken from diseased plants. 



iii. The application of fungicides may be practised in 

 two ways, either as a preventive measure, i.e., before 

 the disease has appeared, or as a curative measure, i.e., 

 for checking the disease after it has made its appearance. 



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