La. Admin. Code tit. 7 § XIII-755

Current through Register Vol. 50, No. 11, November 20, 2024

Section XIII-755 - Sweet Potato Certification Standards (Virus and Non Virus-Tested)

A. The standards for certification of virus-tested and non virus-tested sweet potatoes are the general seed certification standards for roots, plants and cuttings as adopted in Subchapter B of this Part and the following specific standards.

B. The following definitions apply to this Section only.

Certified G0 Plant-a plant grown in a greenhouse and which has been produced by a certified greenhouse grower from a foundation plant.

Daughter Plant-a plant produced by cuttings from a mother plant.

Foundation Plant-a plant that has been produced by the LAES from a virus-tested nuclear stock plant recognized by LDAF if the plant is grown in a greenhouse under strict isolation in a screen cage in which only plants that are virus-tested are grown.

Mericlone-plants clonally propagated from a single meristem tip. For example, mericlone B-63 includes all plants descended from the sixty-third meristemtip culture derived from the variety Beauregard.

Micropropagated-plant multiplication in vitro. The process includes many steps; stock plant care, explant selection and sterilization, media manipulation to obtain proliferation, rooting, acclimation, and growing on. Sweet potato is most commonly micropropagated in tissue culture by aseptic transfer of stem segments containing 1-3 nodes to sterile tissue culture medium.

Mini-Roots-storage roots produced on plants grown in certified G0 greenhouses that may be used to establish certified G2 field plantings.

Mother Plant-a plant obtained from LAES.

Nuclear Stock Plant-plant that is derived from Source Seed and which has been micropropagated, virus-tested, is apparently free of other pests, and has been evaluated in field test for trueness to variety.

Source Seed-material entering the LAES seed program obtained by methods acceptable to LDAF.

Symptomatic Plant-a plant that shows an indication or symptom of a disease, mutation, pest, virus, or other problem that may affect sweet potato production.

Vine Cutting-a section of a vine, preferably 10-12 inches in length, capable of being transplanted.

Virus-Tested -a plant that has been previously tested for the presence of viruses by grafting a sweet potato shoot to the Brazilian morning glory (Ipomoea setosa) on at least three separate occasions and by at least one negative assay by the DNA and PCR assay for sweet potato geminiviruses using the Li et al. method (Li, R., Salih, S., and Hurtt, S. 2004. Detection of geminiviruses in sweet potato by polymerase chain reaction. Plant Dis. 88:1347-1351).

C. Plant Generations

1. Mother plants may be cut repeatedly for no more than five months and the cuttings propagated to produce daughter plants.

2. Daughter plants may be cut repeatedly for no more than five months and the cuttings propagated to produce additional daughter plants. All daughter plants shall be designated as certified G0 and may be used to establish certified Gl field plantings.

3. All plants, vine cuttings and roots produced from mini-roots shall be designated as certified G2.

4. Certified G1 (field generation 1) plantings will be established from certified G0 plants. Vine cuttings may be taken repeatedly from this original G1 planting, to establish a second G1 planting. Vine cuttings may be taken repeatedly from the second G1 planting to establish a third G1 planting. No additional plantings may be established from this third G1 planting. All vine cuttings and roots produced during this first year of field production shall be designated as certified G1.

5. Certified G2 (field generation 2) plantings will be established from certified G1 stocks. Vine cuttings may be taken repeatedly from this original G2 planting, to establish a second G2 planting. Vine cuttings may be taken repeatedly from the second G2 planting, to establish a third G2 planting. No additional plantings may be established from this third G2 planting. All vine cuttings and roots produced during this second year of field production shall be designated as certified G2.

6. Certified G3 (field generation 3) plantings will be established from certified G2 stocks. Vine cuttings may be taken repeatedly from this original G3 planting, to establish a second G3 planting. Vine cuttings may be taken repeatedly from the second G3 planting to establish a third G3 planting. No additional plantings may be established from this third G3 planting. All vine cuttings and roots produced during this third year of field production shall be designated as certified G3.

D. Greenhouse Requirements for Certification of Virus-Tested Sweet Potatoes

1. LDAF must approve greenhouses before mother plants are released to the grower.

2. Mother plants grown in a greenhouse shall be kept isolated in screen cages.

3. Greenhouses used for production of mother plants shall meet the following requirements.

a. The entry points shall use a set of double doors.

b. A system for sanitizing hands and feet prior to entry into the growing areas of the greenhouse.

c. Yellow sticky traps shall be used to monitor aphids and other insects.

d. Screens of such mesh as to prevent entry of aphids shall cover all openings (vents, fans, windows, etc.).

e. A legible signs shall be prominently placed in front of every entrance to each greenhouse so as to be clearly visible by workers and other persons warning them that they shall not enter, if they are coming from the field or from non-certified greenhouses.

f. An integrated pest management program shall be in place to control aphids, whiteflies or other insects with sucking, mouthparts.

g. Cutting tools used in a greenhouse shall be decontaminated on a regular basis and shall always be decontaminated prior to being used on another group of stock plants or plant lots.

h. All growing medium, including benches, containers, etc. used in the greenhouse shall be cleaned by a method approved by LDAF.

i. All plants shall be removed from the greenhouse and the greenhouse kept free of plants for a minimum of six weeks between crop years.

j. No plants shall be allowed to grow within 10 feet of the greenhouse, except for turf grass used for stabilization of the soil.

k. No plants other than mother plants shall be allowed in the greenhouse.

l. Greenhouses shall be a minimum of 200 feet away from sweet potato storage sheds, cull piles or other potential sources of sweet potato viruses unless LDAF approves a closer distance.

m. Different varieties or mericlones must be clearly identified and separated.

4. Producer shall inspect vines twice weekly. If symptomatic plants are found, they shall be removed and destroyed and parent plants shall be inspected for disease symptoms. The grower shall keep a log showing that inspections were made and if plants were removed.

5. Producers shall inspect each greenhouse and its perimeter at least once weekly to ensure that the greenhouse isolation requirements are being met. LDAF shall be immediately notified if an inspection indicates that one or more of the isolation requirements have been breached.

6. LDAF shall inspect certified greenhouses at least once prior to cuttings going to the field and as needed if problems are observed. If symptomatic plants are found during these inspections the grower must rogue and dispose of these plants properly.

7. Once shipping of plants begins, final certification will not be allowed if symptomatic plants are found.

8. A unit of certification shall be the entire greenhouse and such unit cannot be divided for the purpose for certification.

9. Specific Greenhouse Requirements for the Certification of Virus-tested Sweet Potatoes

Maximum Tolerance Allowed
Certified	Foundation Plants (LAES)
Presence or symptoms of:
Bacterial Stem Rot (Erwinia chrysanthemi)*	0	0
Black Rot (Ceratocystis fimbriata)*	0	0
Scurf (Monilochaetes infuscans)*	0	0
Root-Knot Nematode (Meloidogyne spp.)	0	0
Feathery Mottle (sweet potato feathery mottle virus [SPFMV])*	0	0
Russet Crack (a strain of SPFMV)*	0	0
Internal Cork (a virus)*	0	0
Wilt (Fusarium oxysporum f. sp. batatas)*	0	0
Sweetpotato Weevil (Cylas formicarius)	0	0
Exotic or hazardous pests	0	0
Variety mixture	0	0
Off-types (mutations)	0	0

*Plants or mini-roots exhibiting symptoms

E . Field Requirements for Certification of Virus-Tested and Non-Virus-tested Sweet Potatoes

1. Seed Bed Inspections and Standards

a. A seed bed field shall contain only certified sweet potato plants.

b. Prior to planting, seed sweet potatoes shall be treated with an approved pesticide approved by LDAF and in accordance with recommendations from the LAES.

c. Seed beds shall be located at least 100 feet from where sweet potatoes were grown or bedded in the previous two years, and in such manner that there will be no wash from the previous two years' seed beds or fields; or treated in a manner satisfactory to LDAF.

d. At least one seed bed inspection shall be made by LDAF to determine that quality plants are being produced and that the plants are apparently free of injurious insects and harmful diseases. Additional seed bed inspection may be made by LDAF when deemed appropriate by LDAF.

2. Field Production for Certification of Virus-Tested and Non-Virus-Tested Sweet Potatoes

a. Sweet potato seed shall not be eligible for certification if produced on land which:

i. has produced sweet potatoes in the last two years;

ii. has received manure or sweet potato residue in the last two years;

iii. is subject to drainage from fields in which sweet potatoes have been grown in the last two years.

b. Isolation

i. Non virus-tested sweet potato seed production fields shall have a minimum isolation distance of 20 feet.

ii. Virus-tested sweet potato seed production fields shall be isolated by a minimum of 20 feet from sweet potato fields that contain certified but non virus-tested sweet potatoes, and by a minimum of 750 feet from non-certified and non virus-tested sweet potatoes.

iii. If the seed of two virus-tested varieties are grown in the same field, they must be clearly identified and separated by at least 20 feet.

iv. Nuclear stock plants shall be maintained under strict isolation in laboratory facilities approved by LDAF and maintained by LAES and/or any contracted micropropagation provider. The facilities shall be in a clean, dust-free building that is at least 250 feet from any sweet potato field or greenhouse.

c. An LDAF approved program shall be in place to control perennial morning glories (e.g. lpomoea andurata, Bigroot Morning Glory, Ipomoea cordatotriloba sharp-pod or cotton Morning Glory), and volunteer sweet potato plants.

d. Different varieties or mericlones will be clearly identified and separated from each other by a minimum of 20 feet.

e. Each unit of sweet potatoes that has passed field inspection shall be marked or labeled at harvest to correspond with the field unit.

3. Inspections for Certification of Virus-Tested and Non-Virus-Tested Sweet Potatoes

a. The grower shall inspect fields weekly during the growing season and rogue any symptomatic plants that are found. LDAF shall be informed if any problems concerning certification requirements are found.

b. LDAF shall make a minimum of two inspections of each sweet potato seed production field during each growing season.

i. The first field inspection shall be made before vines have covered the ground so that symptomatic plants may be easily identified.

ii. The second inspection shall be made prior to harvest, but as close to harvest as is practical.

c. The unit of certification for production is a field and cannot be divided for the purpose for certification.

d. Specific Field Tolerance Requirements (Vine Inspection)

Maximum Tolerance Allowed
Factor[DAGGER]	G1 Plants		G2 Plants		G3 Plants
	Virus-Tested	Certified	Virus-Tested	Certified	Virus-Tested	Certified
Bacterial Stem Rot	None	None	None	5 plants/ acre	None	5 plants/ acre
Fusarium Wilt	None	None	None	5 plants/ acre	None	5 plants/ acre
Sweetpotato Weevil	None	None	None	None	None	None
Exotic/ Hazardous Pests	None	None	None	None	None	None
Off-Types (Mutations)	0.05%	0.05%	0.05%	0.05%	0.10%	10 plants/ acre
Variety Mixture	None	None	None	10 plants/ acre	None	10 plants/ acre

[DAGGER] If other severe factors are observed at time of inspection, rejection of all or a portion of a field may occur.

F. Storage Requirement for Certification of Virus-Tested and Non-Virus-Tested Sweet Potatoes

1. The procedures for cleaning and sanitizing the structure where sweet potatoes grown for certification are to be stored shall be in accordance with recommendations from the LAES and approved by LDAF and before any such sweet potatoes are stored in the structure.

2. Sweet potatoes grown for certification shall be stored in new containers (crates, pallet boxes, etc.) or used containers that have been cleaned according to sanitation guidelines approved by LDAF.

3. Certified seed roots shall be stored in a separate room from any non-certified roots.

4. Sweet potatoes from different field units shall be separated in storage by an aisle at least two feet wide.

5. LDAF shall inspect a minimum of 20 percent of each lot of sweet potatoes entered for certification during the storage inspection.

G. General Standards for Plants and Seed Roots of Virus-tested and Non-Virus-tested Sweet Potatoes

1. Plants shall be:

a. apparently free of injurious insects, harmful diseases or other significant pests;

b. true to variety characteristics;

c. of good color, fresh, firm, and strong; and

d. of satisfactory size for commercial planting (cuttings approximately 10"-12" long).

2. All such cuttings will be made at least one inch above the surface of the soil or growing medium. Slips that have been pulled are not to be used to avoid the possibility of carrying pathogens or insects that can be present on stems below the soil surface.

3. Cuttings shall be loosely packed, shipped in an upright position in boxes, and shall not be shipped with non-certified sweet potato plants.

4. Seed Roots

a. LDAF shall make one seed root storage inspection after harvest and before shipment.

b. The minimum size shall be one inch in diameter, four inches in length and 30 ounces maximum weight.

c. Specific Seed Root Tolerance Standards of Virus-Tested and Non-Virus-Tested Sweet Potatoes

Maximum Tolerance Allowed for Virus-tested and Non Virus-tested Sweet Potatoes
Presence or symptoms of:	G1 (Foundation) G2 (Certified) Seed Roots	G3 (Certified) Seed Roots
Surface rots (Fusarium spp.) and Soft Rots (Rhizopus spp.)	5%	5%
Bacterial Root Rot (Erwinia spp.)	none	None
Black Rot (Ceratocystis fimbriata)	none	None
Scurf (Monilochaetes infuscans)	1.0%	2.0%
Streptomyces soil rot (Streptomyces ipomoeae)	2.5%	5.0%
Root-Knot Nematode - (Meloidogyne spp.) (Other than Guava Root-Knot Nematode)	1.0%	2.0%
Guava Root-Knot Nematode (Meloidogyne enterolobii)	None	None
Russet Crack (a strain of SPFMV)	None	None
Wilt (Fusarium oxysporum f. sp. batatas)	None	None
Sweetpotato Weevil (Cylas formicarius)	None	None
Exotic or hazardous pests	None	None
Variety Mixture	None	None
Off-types (mutations)	0.20%	0.50%

H. Tagging and Certificate Reporting System

1. An official numbered certificate or tag provided by LDAF shall accompany each sale of certified sweet potato cuttings and seed roots.

a. When issuing official certificates the grower shall:

i. send a copy of each completed certificate to LDAF within 10 days after each sale; and

ii. maintain a copy of each issued certificate on file.

b. A complete record of certified sweet potato cuttings and seed roots sales shall be maintained and made available to LDAF. The record shall include the purchaser's name, the kind and variety/cultivar, the class, the date of shipment, and the number of plants or bushels shipped.

I. Quarantine of Areas Used for Certification

1. If a Sweetpotato weevil is found in any field, greenhouse, seed bed, storage or packing shed, or other structure or area affiliated with the production of certified sweet potatoes or sweet potato plants or within 300 yards of any such structure or area, then the entire area and all structures affiliated with the certification process shall be immediately quarantined in accordance with the Sweetpotato weevil quarantine regulations found in Subchapter C of Part XV of Title 7 of the Louisiana Administrative Code (LAC 7:XV.133 et seq.).

2. If any plant pest or disease subject to regulation or quarantine under Part II or Part III of Chapter 12 of Title 3 of the Louisiana Revised Statutes of 1950, (R.S. 3:1651 et seq.) that may affect sweet potato production is found in any field, greenhouse, seed bed, storage or packing shed, or other structure or area affiliated with the production of certified sweet potatoes or sweet potato plants then the entire area and all structures affiliated with the certification process may be subject to quarantine in accordance with applicable law and regulations.

La. Admin. Code tit. 7, § XIII-755

Promulgated by the Department of Agriculture, Seed Commission, LR 8:579 (November 1982), amended LR 9:202 (April 1983), amended by the Department of Agriculture and Forestry, Office of Agricultural and Environmental Sciences, Seed Commission, LR 12:825 (December 1986), LR 22:1210 (December 1996), LR 36:1220 (June 2010), repromulgated by the Department of Agriculture and Forestry, Office of Agricultural and Environmental Sciences, Agricultural Chemistry and Seed Commission, LR 39:2725 (October 2013), amended LR 40:755 (April 2014), Amended LR 441855 (10/1/2018), AmendedLR 451168 (9/1/2019), Repromulgated LR 451438 (10/1/2019).

AUTHORITY NOTE: Promulgated in accordance with R.S. 3:1433.