§ Squadron Leader Kinghornasked the Secretary of State for the Colonies if he can make a statement about the discovery of an insecticide which has been proved fatal to the mealy bug which is the source of infection to the cocoa trees suffering from swollen shoot disease in the Gold Coast.
Mr. DugdaleAs was announced in November, 1949, a small research unit from Pest Control Limited has been carrying out experiments at the West African Cocoa Research Institute in the Gold Coast in the use of systemic insecticides. The first phase of these experiments has now been concluded. A method of applying the systemic insecticides has been devised and its success in killing mealy bugs has been demonstrated. It will now be necessary to carry out further experiments in order to judge more closely the effect of the insecticides. These may well take a considerable time.
The object of this experimental work is to discover a practicable and effective means of controlling the mealy bugs which carry swollen shoot from one tree to another. It is the mealy bug, and not the virus itself, which the insecticide aims to kill. The insecticide cannot cure a tree once it has become infected by the virus of swollen shoot, and cutting out of diseased trees will, therefore, remain as necessary as ever. The employment of insecticides, if their use on the scale necessary is found to be practicable, may make it easier to prevent the spread of the disease to uninfected trees and this would reduce the total number of trees which 10W have to be cut out before obtaining complete control over the disease. The insecticides can, however, only be used as a supplement to the cutting out campaign and not as an alternative to it.