(2) Such warning shall be deemed to be duly served— (a) if served personally upon the person responsible; or (b) if left addressed to the person responsible at his usual or last known place of abode; or (c) if posted in a prepaid registered letter addressed to the person responsible at his last known place of abode or business. 122An inspector may clear land at expense of person responsible (1) If a person responsible fails to clear land in accordance with a warning made in terms of subsection (3) of section one hundred and nineteen, an inspector may, upon receiving written authority from the Minister, enter upon the land with or without assistance and eradicate any invasive alien species found therein. (2) Nothing contained in subsection (1) shall relieve the person responsible from any penalty he may have incurred under this Part, and the Minister may recover the cost, charges and expenses of clearing the infected land by action in a competent court. 123Prohibition on placement of invasive alien species in any watercourse or any road (1) No person shall place or cause or permit to be placed any invasive alien species or the seed of any invasive alien species— (a) in any river, stream or irrigation canal or any other watercourse; or (b) on any road or land. (2) Any person who contravenes subsection (1) shall be guilty of an offence and liable, if the offence involves— (a) an invasive alien species or seed of an invasive alien species specified in Part III of the Fifth Schedule, to the penalties specified in paragraph (a) of subsection (2) of section one hundred and nineteen ; or (b) an invasive alien species or seed of an invasive alien species other than an invasive alien species specified in Part III of the Third Schedule, to the penalties prescribed by paragraph (b) of subsection (2) of section one hundred and nineteen. 124Power to take samples of seed and treatment of plant, seed or grain offered for sale (1) An inspector may, at all reasonable times enter any premises where any plant, seed or grain is offered for sale, and may take samples thereof. (2) If an inspector finds offered for sale any plant, seed or grain, which is likely to propagate or spread the growth of an invasive alien species, such plant, seed or grain shall, when considered necessary by the inspector, be treated by or at the expense of the consignee or vendor, in the manner prescribed by or to the satisfaction of the inspector. (3) If the plant, seed or grain is not treated in terms of subsection (1) or if such treatment is deemed ineffectual, the Minister may by written order served on the consignee or vendor, cause such plant, seed or grain to be destroyed. 125Local authorities authorised to make by-laws Every local authority shall have power to make by-laws compelling occupiers of land within the area of the local authority to keep their land free from invasive alien species. 56