North Dakota Administrative Code › Title 74 - Seed Commission › Article 74-04 - Seed Potato Certification Standards › Chapter 74-04-01 - Seed Potato Certification Standards › Section 74-04-01-08 - Field inspection standards

Current through Supplement No. 393, July, 2024
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
1.0
Leaf roll (PLRV)
0.2
0.3
0.4
0.5
0.5
0.5
1.0
Total serious virus
0.2
0.3
0.4
0.5
0.5
0.5
1.0
*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
1.0
Leaf roll (PLRV)
0.0
0.1
0.2
0.3
0.3
0.3
1.0
Total serious virus
0.0
0.1
0.2
0.3
0.3
0.3
1.0
*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.