For regulation 18(6)(a) (Prevention of marketing of sub-standard potatoes and the prevention of spread of disease by marketing of potatoes) there shall be substituted the following:—
(a) in relation to the pests and diseases specified in Group III of Part I and Group V of Part II of Schedule 5 deem a potato in any such sample not to be affected by disease when in his opinion—
(i) less than one-eighth of its surface area has been affected, and
(ii) it has at least 2 eyes at the rose end wholly unaffected by the disease;
(aa) in relation to the pests and diseases specified in Group IV of Parts I and II of Schedule 5 deem a potato in any such sample not to be affected by disease when in his opinion—
(i) less than one-quarter of its surface area has been affected, and
(ii) it has at least 2 eyes at the rose end wholly unaffected by the disease;