SECOND SCHEDULE (Regulations 7, 8, 10 and 11) STANDARDS FOR CERTIFICATION OF POTATO SEED QUALITY CLASS (Code) S1 (S2, S3) SE E1 E2 A B FIELD INSPECTION Defect Index Isolation (highest (metres) value) 150 1 100 4 100 8 100 8 100 12 50 30 VIRUS POST CONTROL Maximum severe virus diseases % 0.1 0.8 - TUBER CONTROL CONTROL Defect Index (highest value) 10 10 10 10 15 20 GROWING Defect Index (highest value) 3 8 15 15 - NOTES: Field inspection 1. The isolation refers to the distance between the potato crop for certification and potato crops of lower quality classes or volunteer potato plants. Between different cultivars of the same quality class the isolation shall be at least 5 metres. 2. A potato crop will be considered heavily infested with aphids if there are more than 150 per 100 leaves taken from the lower half of a plant. Provided that haulm destruction of a heavily infested crop is carried out within seven days from the date of discovering by inspection, it may be cleared by field inspection. 3. Undesirable plants shall be cleared away as soon as possible by removing both the haulms and the tubers to a distance of at least 30 metres from every edge of the field. 4. Diseased plants, plants of other cultivars and off type plants shall be recorded as percentages by number; and the percentages found shall be multiplied by the appropriate factors set out in note 5, and the various products so obtained shall be added together to give the defect index for the particular field. 5. The factors to obtain the defect index for a field inspection shall be as follows: Defect Leaf roll virus (PLRV).................................................. Severe mosaic (PVY).................................................... Black leg ....................................................................... Factor 10 8 3