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Plant Improvement Act, 1976 (Act No. 53 of 1976)

Notices

South African Seed Potato Certification Scheme

19. Field sample

 

(1) In the case of a field sample to determine the virus status of a unit
(a) the grower must notify the authority forthwith when the top growth of plants has died off or has been destroyed and the skins of the tubers have set;
(b) the grower must forthwith  make an appointment with the authority to draw the virus field sample;
(c) a representative tuber sample must be taken in accordance with the provisions of the protocol;
(d) only one tuber per plant shall be taken;
(e) unless otherwise determined by the authority, the size of the sample for testing for certification shall, in the case of—
(i) G0 seed potatoes, be 2 tubers per 100 plants or a portion thereof;
(ii) G1 and G2 seed potatoes, be 400 tubers per 2.5 hectares or a portion thereof;
(iii) G3 seed potatoes, be 400 tubers per 5 hectares or a portion thereof; and
(iv) G4, G5, G6, G7 and Certified Commercial seed  potatoes, be 200 tubers  per 5 hectares or a portion thereof.
(f) the grower may request that the sample size applicable to G3 seed potatoes referred to in paragraph (e)(iii) be taken for G4, G5, G6, G7 and Certified Commercial seed potatoes;
(g) in the case of greenhouse plantings (potato micro-propagative material planted), the grower may request that leaf samples be taken, in which case the size of the sample for testing for certification shall be 2 composite leaves per 100 plants or a portion thereof, and tested in accordance with the prescriptions of the protocol for the presence of viruses instead of testing tubers;
(h) in the case of TSWV detected during field inspection, the virus field sample will be tested for TSWV in accordance with recognised methods;
(i) on units smaller or equal to 0.5 hectare, the sample size shall be as follows—
(i) 80 tubers for plantings less or equal to 0.1 hectare;
(ii) 160 tubers for plantings bigger than 0.1 hectare to 0.25 hectare;
(iii) 240 tubers for plantings bigger than 0.25 hectare to 0.4 hectare;
(iv) 320 tubers for plantings bigger than 0.4 hectare to 0.5 hectare; and

if more than 0.5 hectare, the normal sample size applies; and

(j) in the case of regrowth, the field sample result will be ignored, and certification shall only be awarded on a favourable virus store sample result.

 

(2) In the case of a field sample to determine the presence of Ralstonia spp. in the case of G0 to Certified Commercial seed potatoes, and to determine the presence of SRE in the case of G0 seed potatoes
(a) the grower  must forthwith  make an appointment with the authority  to draw the bacterial sample;
(b) the sample shall be taken as late as possible during the growing season or after the foliage has died off and the skins of the tubers have set;
(c) one sample shall be taken in accordance with the provisions of the protocol from plantings on a unit or units within the isolation area;
(d) only one tuber per plant shall be taken; and
(e) unless otherwise determined by the authority, the size of the sample shall, in the case of—
(i) G0 seed potatoes, be 4 tubers per 100 plants or a portion thereof;
(ii) G1 seed potatoes, be 1 tuber every 10 metres in each row to a maximum of 4 605 tubers over the whole planting;
(iii) G2 to Certified Commercial seed potatoes, be 4 605 tubers taken in accordance with the provisions of the protocol in plantings on a unit or units in the isolation area; or
(iv) G2 to Certified Commercial seed potatoes planted on units of 1 hectare or smaller, be 1 tuber every ten meters in each row to a maximum of 4 605 tubers over the whole planting.

 

(3) In the case where the growth stages of seed potatoes on units in the isolation area overlap, certification of such seed potatoes may only take place once field sample results of all the units concerned are known and the provisions of section 24 have been complied with.

 

(4) All field samples must be taken according to the  prescriptions of the protocol, under supervision of a certification official or a person designated by the authority.

 

(5) Where a sub-unit, or a unit within the isolation area, is rejected or withdrawn from certification, bacterial wilt samples must be taken on the rejected or withdrawn unit prior to harvesting. Failure to comply will result in the termination of the certification process on all units concerned.