Sec. 97.4. Field standards

(a) General.

(1) The field shall be considered the unit of certification. A field cannot be divided for purposes of certification unless satisfactory isolation exists.

(2) Isolation:

(i) Wheat, oats, barley, triticale, spelt. A strip of ground adequate to prevent mechanical mixtures, but no less than three feet wide, which is either mowed, uncropped, or planted to some crop other than the kind being certified, must be present between any plantings of wheat, oats, barley, triticale or spelt, and any other such plantings or combination of plantings.

(ii) Rye. A field producing any class of certified seed must be isolated by at least 660 feet from fields of any other variety or the same variety of lower certified seed class.

(3) A field producing either foundation or registered seed being grown from seed which has been treated for the control of loose smut shall be isolated at least 330 feet from other fields or the same crop which are not planted to treated seed.

(b) Specific requirements.

Maximum permitted in each class
Factor	Foundation	Registered	Certified
Other varieties	none	0.02%	0.05%
Inseparable other crops	none	none	0.03%
Prohibited weeds	none	none	none
Seed–borne diseases:
1. Common bunt or stinking smut of wheat	0.001%	0.01%	0.10%
2. Loose smut of wheat	0.10%	0.25%	0.50%
3. Dwarf bunt in wheat	none	none	1 plant/acre

1

Other varieties shall be considered to include offtype plants not typical of the variety that can be differentiated from the variety that is being inspected.

2

Inseparable other crops shall include crop plants, seed of which cannot be thoroughly removed by the usual methods of cleaning. Winter barley and winter wheat fields shall be free of rye.

3

Certified small grain fields shall be free of corn cockle (Agrostemma githago), wild onion and/or garlic (Allium spp) and the following vetches: hairy (Vicia villosa), narrow leaf (V. angustifolia), and common (V. sativa).

Notation

1

Other varieties shall be considered to include offtype plants not typical of the variety that can be differentiated from the variety that is being inspected.

2

Inseparable other crops shall include crop plants, seed of which cannot be thoroughly removed by the usual methods of cleaning. Winter barley and winter wheat fields shall be free of rye.

3

Certified small grain fields shall be free of corn cockle (Agrostemma githago), wild onion and/or garlic (Allium spp) and the following vetches: hairy (Vicia villosa), narrow leaf (V. angustifolia), and common (V. sativa).