Field inspection standards

1. Each seed potato field will be visually inspected based on sample inspection. The method of inspection and sample size will be at the discretion of the state seed department but a minimum of one hundred plants per acre [.40 hectare] will be inspected. For varieties that do not express readily visible symptoms of a disease, laboratory testing may be done for the pathogen. 2. The field tolerance established will be based on visible symptoms in the samples inspected. Diseases which cannot be observed visually may be present. First Inspection Tolerances (%) Foundation Class Field Year Certified Class Field Year 1 2 3 4 5 6 0-6 Varietal mixture 0.1 0.2 0.3 0.5 0.5 0.5 0.5 Spindle tuber viroid 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Severe mosaics (PVY) 0.2 0.3 0.4 0.5 0.5 0.5 2.0 Leaf roll (PLRV) 0.2 0.3 0.4 0.5 0.5 0.5 2.0 Total serious virus 0.2 0.3 0.4 0.5 0.5 0.5 2.0 *Bacterial ring rot 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Second and All Subsequent Inspections Tolerances (%) Foundation Class Field Year Certified Class Field Year 1 2 3 4 5 6 0-6 Varietal mixture 0.1 0.1 0.2 0.3 0.3 0.3 0.3 Spindle tuber viroid 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Severe mosaics (PVY) 0.0 0.1 0.2 0.3 0.3 0.3 2.0 Leaf roll (PLRV) 0.0 0.1 0.2 0.3 0.3 0.3 2.0 Total serious virus 0.0 0.1 0.2 0.3 0.3 0.3 2.0 *Bacterial ring rot 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Late blight found during field inspection must be confirmed by symptoms or laboratory diagnosis before being reported on the inspection report. * The zero tolerance means that no amount is permissible when inspected. It does not mean that the seed is absolutely free of disease or disease-causing agents, but that none was found during inspection. Varieties that do not express visible disease symptoms. Potato varieties that do not express visible disease symptoms of a specific pathogen may be subjected to a laboratory test to determine the levels of the pathogen in a seed lot. This testing may occur during the growing season or during the winter test, or both, and may affect eligibility of the seed lot. Ring rot. Seed fields will be subject to a third (final) field inspection focused primarily on inspection for symptoms related to ring rot. If the field has not received a third inspection, the grower will be required to submit a four hundred tuber sample (minimum) per field for laboratory testing. Blackleg. Since the blackleg disease may be latent, the inspector will record only the percentage observed during the first and second inspection, and no tolerance will be established. However, any excessive amount can be cause for rejection. Blackleg observations shall be based upon sample plants exhibiting the characteristic black, inky, soft, slimy, decomposed tissue of the stem. Wilt. Only the percentage noted will be recorded on the first and second inspection, and may include other factors such as maturity, drought, or alkali problems but any excessive amount may be cause for rejection. There will be zero tolerance for potato wart, corky ring spot, gangrene, golden nematode, root knot nematode, tuber moths, or other such injurious pests that have never been found and confirmed in North Dakota seed potato fields. Tolerances for potato virus x tested seed. All of the above tolerances will apply, including a requirement that bacterial ring rot must not have been found on the farm during the season. Seed lots with no more than two percent potato virus x infection may be identified as virus x tested on certification labels. 3. Field conditions. a. Insect control must be maintained early and until the vines are killed or matured. Fields suffering excessive insect injury may be disqualified for certification. A grower will notify the inspector of the date of spraying and spray material applied. b. Vine killing. If a field has not received final inspection, the grower must obtain approval from the inspector before killing the vines. Furthermore, if the inspector deems it appropriate, a laboratory test may be required or strips of unkilled vines must be left in the seed fields to facilitate final inspections, or both. When strips are left for inspection, the first twelve rows (if a six-row planter was used, eight rows if a four-row planter was used) must not be vine-killed. It will be the responsibility of the seed producer to identify where seed planting began. Approximately ten percent of the seed field acreage must be left in strips. c. Any condition such as excess weeds, hail injury, foreign plants, chemical damage, soil conditions, or insect damage that interferes with proper inspection may disqualify the seed for certification. d. Roguing is permitted and recommended in many cases but must be done before the inspector arrives in the field. e. Presence of disease or conditions not mentioned heretofore which may impair seed quality shall constitute cause for rejection or additional testing before final certification. Stocks which show an excessive percentage of total serious virus in official postharvest tests shall be considered ineligible for certification. 4. Appeal. Inspection of rejected fields will be considered, provided application is made within three days after rejection, the field is in good condition for inspection, and no additional roguing is done prior to reinspection. 5. Bacterial ring rot control. a. All seed produced by a farming operation in which bacterial ring rot has been found will be ineligible for recertification the following year. b. If the farming operation is found to be infected, all equipment and storages must be cleaned and disinfected. c. A farming operation found to be infected on three consecutive years shall be required to purchase all new seed, clean, and disinfect the operation under the supervision of the state seed department before entering any seed for certification. 6. The variety name stated on the application will be the standard for inspection when entering the field. Absent compelling visual evidence to the contrary, the variety or selection declared by the grower will be presumed correct if the documentation provided is valid and the variety description characteristics meet the requirements of the chapter. 7. Inspections, tests, certifications, and other acts are not intended to induce reliance on the seed department's inspections, certifications, or any other action or inaction for any purpose relating to quantity or quality of the seed or crop produced, fitness for purpose, merchantability, absence of disease, or variety or selection identification. Certification means only that the potatoes were randomly inspected, and at the time of the inspection the field or seed lot met the rules of the department.