is produced. After the branches are dead and even after 

 they have fallen the fungus continues to produce its 

 perithecia, which appear as small, black structures bursting 

 through the bark. 



On the pods the disease is known as "brown rot"; it 

 makes its appearance in the form of a discoloured patch at 

 one or other end of the pod or at a wound on its surface. 

 The discoloured area increases in size and extends over the 

 greater part of the surface. Pods may be attacked in 

 nearly all stages of development ; young pods, when once 

 affected, seldom mature ; older pods, however, which are 

 attacked when near to maturity may be allowed to ripen. 



The fungus effects an entrance into the stem only at a 

 wound ; in the case of the fruit, however, it would appear 

 that, in addition to entering at a wound, it is also capable 

 of entering the pod either through the basal or stigmatic end. 

 Diplodia cacaoicola is regarded by some authors as 

 identical with other species ; Griffon and Maublanc (1909) 

 consider Botryo diplodia Thcobromcs, Pat., Macrophoma 

 vestita, PRILL, and DEL., Lasio diplodia nigra, APPEL and 

 LAUBERT, and Diplodia cacaoicola, P. HENN, as being 

 identical ; Petch regards Botryodiploaia elasticce, to which 

 he has attributed the later stages of a " die-back " disease 

 of Hevea brusiliensis, as indistinguishable from Diplodia 

 cacaoicola ; Van Hall considers that the species of Diplodia, 

 Lasiodiplodia and Chaeto diplodia occurring on cacao are 

 identical. 



The life-history of the fungus is at present incomplete, 

 and it is most important that it should be thoroughly 

 worked out. If we are to be guided by the principle of 

 analogy, then the fungus would be expected to possess a 

 small, perithecial form belonging to the genus Phoma, or to 

 some allied form-genus, possibly one or more conidial 

 forms and an ascigerous form belonging to the Sphceriacea. 



A knowledge of the life-history may considerably affect 

 the method of treating the disease. At present the 

 remedial measures practised are : 



(i.) Careful cultivation, manuring and pruning, so as to 

 ensure a vigorous growth of the plant. In a recent 

 publication Mr. Van Hall considers that only leafless and 

 unhealthy trees are affected by the fungus. 



(ii.) Sealing of all wounds made during pruning and 



such as may arise from other causes. 



(iii.) Removal of diseased branches (these are to be 



cut off at a distance of at least six inches below the 



nearest dead end), pods and shells, and their burial in 



pits with lime. 



39 



