Cacao Disease in the Gold Coast

Abstract

THE Commission on Swollen Shoot Disease of Cacao (see Nature of October 30, p. 689) arrived in the Gold Coast at the end of October and left Accra on December 5. On December 3, it held a Press conference in Accra and the following statement was issued : "The Swollen Shoot Commission has now been at work for about six weeks. During that time it has examined a vast mass of evidence and has heard from representatives of all the groups of people concerned—farmers, scientists at the West African Cacao Research Institute, survey officers, and agricultural officers. . . . The undisputed fact is that swollen shoot is a contagious disease of the virus type. Drought, Akate, old age, lack of canopy and poor soils have nothing whatsoever to do with it. The virus causing this disease is present in all parts of a diseased tree, and once it has established itself it cannot be eliminated except by the destruction of the tree in which it lives. How then does a tree become infected? There is only one way in Nature whereby this can be done and that is by the feeding of an infected mealybug on a healthy tree. Not all mealybugs, of course, are infected. They can become infected only by feeding on a diseased tree, and before they can infect another tree they must move from the diseased tree to a healthy one. How then can such a disease be controlled? With this type of virus disease, the basic method of control is to remove all possible sources of infection. In the case of swollen shoot this means diseased cocoa trees, and in addition, certain wild forest trees which are known to carry swollen shoot infection, this being the only way in which healthy trees can be protected from infection. The Commission will include in its final report a discussion of means which may be of some use for the sanitation and rehabilitation of cocoa in the future, but it is certain that these measures can only be additional to the cutting out. . . . The Commission‘s gravest concern is with the cutting out programme itself. We have to stress that even this method can save the cocoa culture only if it is done accurately, thoroughly and continuously, and without delay. . . . The Commission has spent a long time at the Research Institute at Tafo and has studied very thoroughly all their investigations. We have a great appreciation for the splendid work being done and we strongly advise the cocoa farmers to have confidence in these scientists, who are working solely in the interests of the cocoa farmers of the Gold Coast.—G. H. Berkeley, Walter Carter, E. Van Slogteren."