270 



COCOA DISEASES. 



The attention of the cocoa planters is invited locally to a disease 

 of the pod which has lately been noticed. 



It may be more prevalent than planters are themselves aware 

 of, and there is the certainty of its spreading unless measures are 

 taken to prevent it. 



The disease is due to a fungus,* which was described and 

 figured by Mr. George Massee of the Kew Herbarium in the Kew 

 Bulletin,! and later in his " Text-book of Plant Diseases," from 

 specimens sent from Trinidad by Mr. Hart.:J: 



The disease is recognized by a darkening of the pod which 

 spreads from one end, and by a delicate white mould which 

 appears on the outside. The mould produces immense numbers 

 of very minute particles, lighter than dust, which are blown off by 

 every breath of air and scattered on the pods all round, even at 

 great distances if the wind is high. These particles infect the 

 pods they fall upon ; the disease grows all through the shell, 

 killing young pods, and even in almost mature pods affecting the 

 cocoa beans, causing inferior grade and light weight. These 

 particles falling on a dry pod will do no harm, and therefore wet 

 weather, moist situations, and overhead shade encourage infection. 

 The spread of the disease is due also to other particles, which lie 

 dormant for some time in the substance of the shells of the pods. 

 Like seeds, under favourable conditions and after a resting stage, 

 when the shell decays, they germinate, producing more particles 

 that are carried about by the wind. 



To prevent the spread of the disease, all diseased pods should 

 be picked and either burnt, or buried so deep that they will not be 

 brought to the surface again. All shells from which the beans 

 have been removed should always be buried to ensure that the 

 disease is not propagated by the germination on them of the wind- 

 borne particles, or in them of any of the resting particles. 



If these measures are rigidly carried out, the disease will 

 probably not give any trouble, but if on any estate the disease is 

 found to be wide-spread, all the pods which are not picked off, 

 should be sprayed with Bordeaux mixture, § and a constant watch 

 kept against the breaking out of the disease. 



THE VALUE OF MULCHING WITH LEAVES 



GRASS, &c. 



It has frequently been pointed out of late years in the Bulletin,! 

 and by the Agricultural Instructors that mulching the ground with 

 vegetable refuse is of the greatestf lvalue to the crops grown on it. 

 The practice has been carried out on coffee plantations, and also 



* Phytophora omnivora 

 t Jan. & Feb. 1899. 



t See also W. Indian Bulletin, VI. 1 page 86. 



S For method of preparing Bordeaux mixture see Bulletin for last February page 3 2. 

 \\ For instance, in " The question of Shade for Coffee and Cocoa," Bulletin, Vol, I, 

 June & July, 1903, page 124. 



