(1)This Act shall have effect for the control in Great Britain of pests and diseases injurious to agricultural or horticultural crops, or to trees or bushes, and in the following provisions of this Act—
(a)references to pests are to be taken as references to insects, bacteria, fungi and other vegetable or animal organisms, viruses and all other agents causative of any transmissible disease of agricultural or horticultural crops or of trees or bushes, and also as including references to pests in any stage of existence;
(b)references to a crop are to be taken as including references to trees and bushes.
(2)The competent authorities for purposes of this Act shall—
(a)as regards the protection of forest trees and timber from attack by pests, the Forestry Commissioners (" timber " for this purpose including all forest products) ; and
(b)otherwise, for England and Wales the Minister of Agriculture, Fisheries and Food and for Scotland the Secretary of State.