1. A. General standards. The general standards as adopted in this chapter are basic and applies to sweet potato.

   Only the foundation and certified classes of seed will be recognized. Certified seed or plants shall not be more than two generations removed from foundation seed. (This applies only when foundation seed is available, otherwise certified seed may be produced from certified seed as many years as the required standards are met). Seed potatoes shall be treated prior to bedding. Production fields shall be planted from vine cuttings or with pulled sprouts that have been treated. All chemical treatments used shall be approved by the research division at Virginia Polytechnic Institute and State University or the Virginia Truck and Ornamental Research Station.

2. B. Land requirements. Fields to be eligible for certification shall not have been in the production of sweet potatoes or received sweet potato residue or animal manure or drainage water from sweet potato fields for the three previous years.

3. C. Field standards.

   1. 1. Plant bed and plant stands.

      1. a. Plant bed inspections. At least one inspection shall be made. Beds which show the presence of black rot, stem rot, scurf, or varietal mixture will be rejected.
      2. b. Plant beds shall be moved each year or old plant beds may be used if disinfected by use of chemicals, provided all the old bedding material, roots and plants are removed within 30 days of the final pulling. New bedding medium will be taken from an area which will meet the minimum standards set forth in subsection B.

      3. c. Plant standards. If plants are to be sold:

         1. (1) Plants shall be free of varietal mixtures, injurious insects and the diseases, black rot, scurf, and stem rot.
         2. (2) Plants shall be fresh, of good color and satisfactory size for commercial planting (suggested length approximately 8 inches to 12 inches).

   2. 2. Post-plant bed standards.

      1. a. Field inspection. At least one field inspection shall be made and the following requirements shall be met:
      2. b. Isolation. All fields for certification shall be separated from other sweet potato fields by at least an eight-foot strip in which no sweet potatoes have been planted.

      3. c. Specific.

         		Maximum number of hills/A
         	Factor	Foundation	Certified
         	Other Varieties	None	None
         	Mutations	None	5
         	Stem rot (wild, blue stem)	None	5
         	Georgia Mosaic (Yellow dwarf)	None	None

4. D. Seed storage standards; general requirements.

   1. 1. Different varieties and lots shall be labeled and shall be separated by an aisle of two or more or other means acceptable to the certifying agency. Seed potatoes shall be stored in new containers or in used containers that have been treated.

   2. 2. Storage inspection.

      1. a. At least one inspection shall be made after January 1.

      2. b. Seed for sale shall be graded to meet the following standards:

         	Factor	Size in inches
         	Diameter (maximum)	2 1/4
         	Diameter (minimum)	1
         	Length (maximum)	9
         	Length (minimum)	3

         The length is measured from the ends where the root is about 3/8 inches in diameter.

      3. c. The following standards are applied to the graded roots which shall have good external and internal color:

         		Maximum
         	Factor	Foundation	Certified
         	Black rot	None	None
         	Scurf	None	1:1000
         	Stem rot (wilt, blue stem)	None	None
         	Soil rot	1:100	5:100
         	Surface rot	1:100	5:100
         	Internal breakdown	1:100	5:100
         	Internal cork* (surface area index)	1	1
         	*A one-bushel representative sample shall be shipped to the Virginia Truck Experiment Station, Virginia Beach, Virginia, not later than December 1. Internal cork reading will be made prior to storage inspection.

Statutory Authority

§§ 3.2-4024 of the Code of Virginia.

Historical Notes

Derived from VR172-01-01 § 9, eff. April 1980.