Black pot rod disease affects the cocoa pods seriously in all countries inducing average losses above 30%.
The attack by disease may result in a direct loss of crops as with Phytophthora pod rod and other pod diseases, or the tree may be debilitated , as with vascular –streak dieback.
In West Africa the best known virus disease of cocoa crops is swollen shoot.
The first recognizable symptoms of the disease are swellings on the branches and twigs and leaves become asymmetrical. Later chlorosis takes the form of blotching or spotting.
Water plays an important role in the spreading of the fungus from one pod to another and in the actual infection of the pod itself. The best known fungal disease also effects cocoa. This is black pod whose severity has been known to be closely related to the intensity of rainfall, particularly in the months of July and August.
To counter diseases it is first necessary to identify the cause, then to assess the damage likely to be caused; possible control measures should be examined.
Some diseases such as the virulent forms of virus are very difficult to control, and the diseased trees have to be cut down but even then it is difficult to eradicate the disease.
Diseases of cocoa crop
