“nurseryman” means the owner or other person responsible for the management of a nursery; “nursery stock” means woody perennial plants grown or cultivated for the purpose of trade; “owner” in relation to land or premises includes a joint owner, part owner, lessee or occupier, or the agent of such owner, joint owner, part owner, lessee or occupier; “pest” means an injurious organism which has been declared to be a pest under subsection (2); “phytosanitary certificate” means a certificate issued by an officer of the plant protection service of Malawi, or of any other country concerned, as to the health of a plant or a growing medium; “plant” means any member of the vegetable kingdom, whether living or dead, and includes any part of a plant, or the fruit or flowers thereof, whether severed therefrom or not, and any unmanufactured plant product; “quarantine area” means an area declared to be a quarantine area under this Act; “vehicle” includes an aircraft or a railway train. 2. For the purposes of this Act, the Minister may, by notice, declare any injurious organism to be a pest either generally or in respect of a particular type of plant and either with a view to its control or the prevention of its introduction or spread, or for some other purpose. Inspectors 3. (1) The Minister may, in writing, authorize any person to exercise the powers or perform the duties of an inspector under this Act, or such of them as shall be specified in such written authorization. (2) Every inspector shall, in the exercise of his powers or the performance of his duties under this Act, comply with any directions or instructions which the Minister may from time to time issue for the purposes of this Act. Duties of owners 4. (1) An owner of land or premises shall take all measures prescribed or required by or under this Act, and such additional or alternative of land 3