114 



Report on the Fungoid Diseases of Cacao in Grenada by the 



m ycologi&t. 



In accordance with instructions received from the Imperial Commis- 

 sioner of A griculture for the West Indies, I left Barbados for Grenada 

 on Thursday, February 13th. I arrived in that island on Friday, 

 February, 14th, and left on Friday, March 15th. I was therefore en- 

 gaged on this service fo 31 days in all. During this time, I visited 

 some nineteen estates in various parts of the island, as well as several 

 small holdings in the Grand Roy valley and in the neighbourhood of 

 Greenville . . 



I was able to examine the trees in all the chief Cacao districts 

 in the island and to gain a fairl} r accurate idea of the economic 

 importance of tbe fungoid diseases of that crop The remainder of 

 my time was spent at the Botanic Station where I improvised a small 

 laboratory for the microscopic work and carried out infection experi- 

 ments on healthy cacao trees and pods. 



Three distinct fungi were found to be attacking Cacao, and, in the 

 f ollowing, it is proposed to give a very brief and simple account of 

 these'diseases and to suggest the remedial measures which the nature 

 of the case demands. I propose to speak of these Fungi as (a) the 

 " brown rot" fungus of the pod ; (b) the " canker" fungus of the stem ; 

 and (c) the " root fungus" respectively." 



In order to make what follows more clearly understood, it will not 

 be out of place to point out that the Fungi are a large group of the 

 lower plants which are characterised by the entire absence of green 

 colouring matter and which includes (1) forms which live only on 

 living plants and animals (parasiies) ; (2) those which live only on 

 dead vegetable or animal matter (saprophytes) ; and (3) forms which 

 are intermediate between these two classes and which live either on 

 dead matter or on living plants and animals according to circum- 

 stances. To this latter class belong the fungi attacking the Cacao in 

 in Grenada which are dealt with in this report. The vast majority of 

 the fungi are so minute that recourse has to be had to the microscope 

 for their study and this no doubt accounts for some of the misconcep- 

 tions met with as to the nature of this group. In place of the roots, 

 stem and leaves of a flowering plant, we find in a fungus a network of 

 very minute branched tubes which penetrate the tissues of the material 

 (whether dead or living matter) on which it lives. We can regard 

 these blanched tubes as the " roots" of the fungus,* which in the case 

 of fungi which attack plants are found to extend through the tissues 

 of the part attacked, to live on the materials found therein and to 

 cause so great a disturbance in the normal processes going on in the 

 attacked plant (the host) that the victim is either killed outright or a 

 distorted unproductive plant results, which is quite useless from the 

 point of view of the agriculturist. As a general rule reproduction in 

 fungi takes place by means of minute bodies called spores which cor- 

 respond roughly to the seeds of the higher plants and which are so small 

 that they easily float in the air. In the absence of direct sunlight and 



* This portion constitutes what is known as the mycelium or that part of the 

 fungus which is engaged in absorbing nourishment from the dead or living matter 

 on which it lives. The minute branched tubes making up this mycelium are 

 known as hyphae. 



