190 COCOA 



CHAP. 



control of the canker by cutting out the diseased part 

 of the stem is a matter of continuous care on the part 

 of the planter. 



But besides these special methods different in 

 different countries, according to the special character 

 of the prevalent disease there are a few " hygienic " 

 measures whose adoption may be recommended for 

 every cocoa -growing country. These may be briefly 

 summarised as follows : 



1. Make it as difficult as possible for infection to 

 penetrate into the tree, by removing the dead branches 

 and twigs, and by closing the wounds by means of an 

 antiseptic coating, for which purpose coal-tar is most to 

 be recommended. Several parasitic fungi, as well as 

 noxious insects, find it much easier to enter the tree and 

 attack the healthy tissue when they can begin their 

 invasion with dead wood or at open wounds. 



2. Do not leave the fruit-husks unburied in the 

 plantation. In every cocoa-growing country the pods 

 are attacked by fungi. Phytophthora (causing the 

 " blackening of pods " and the " canker " of stems) 

 is the most common of the fungi which live and pro- 

 pagate on the fruit-husks. The open heaps of fruit- 

 husks, as they are met with on many plantations, 

 may therefore be considered as sources of pod and 

 stem diseases. The best method of disposing of the 

 husks has been the subject of controversy whether 

 simply to bury them (Fig. 62) or to gather them into 

 compost heaps, mixed with lime. The latter method, 

 of course, involves more labour, for the shells have 

 to be collected into heaps and later to be spread over 

 the field again. The present author can see no special 

 advantages in this laborious method, and considers 

 the simple method of burying the best. A practical 

 way is to make the holes in which the husks are to 

 be buried between the rows of cocoa, and to alternate 

 with each following picking, in order to divide the husks 

 as equally as possible over the field. The husks are 

 valuable as manure, as they contain about 0*2 per cent 



