35.—(1) No person shall sell or offer or expose for sale or knowingly cause or permit to be sold or offered or exposed for sale as potatoes of an approved immune variety any potatoes which are not of an approved immune variety.
(2) A person shall not be liable to conviction for a contravention of article 34(2) if he proves to the satisfaction of the court that the potatoes were sold to him as potatoes of an approved immune variety and that he did not know that the potatoes were not of an approved immune variety.