Chapter 16-350 WAC

(1) Trees of Malus, Pyrus, Cydonia, Chaenomeles, Amelanchier, Crataegus, Sorbus or Prunus may be registered as rootstock and scion sources for the propagation of certified nursery stock when inspected, tested and found to be discernibly free from harmful virus and virus-like diseases and other conditions by procedures outlined in this program.

(2) Issuance of a certified state of Washington plant tag, stamp or other document under this chapter means only that the tagged, stamped or otherwise documented fruit tree or fruit tree related ornamental stock and rootstock have been subjected to procedures and requirements described in this chapter and determined to be in compliance with its standards and requirements. The department disclaims all express or implied warranties, including without limitation implied warranties of merchantability and fitness for particular purpose, regarding all plants, plant parts, and plant materials under this chapter.

(3) The department is not responsible for disease, genetic disorders, off-type, failure of performance, mislabeling or otherwise, in connection with this chapter. No grower, nursery dealer, government official, or other person is authorized to give any expressed or implied warranty, or to accept financial responsibility on behalf of the department regarding this chapter.

(4) Participation in the fruit tree planting stock certification program is voluntary.

(1) "Block" means a contiguous grouping of registered plants separated by at least 10 feet from other contiguous groupings of registered plants. Exemptions for closer spacing of registered plants may be granted by the department when risks of infection from targeted pests is low and plant spacing is consistent with current industry standards.

(2) "Clean cultivation" means the site is bare earth or is planted with a grass (Gramineae) or another crop approved in writing by the department in which broad-leaved weeds are actively controlled.

(3) "Department" means the Washington state department of agriculture.

(4) "Diagnostic assays" means those tests used to detect viruses and virus-like pathogens and may include use of herbaceous or woody indicator plants, serological tests, polymerase chain reaction assays, high throughput sequencing, canine detection, and/or other scientifically validated means.

(5) "G1" refers to the original plants (nuclear materials) plant line, variety, or cultivar that has been:

(a) Tested for, and found free of, economically important and/or harmful plant viruses and virus-like organisms; and

(b) Been maintained under controlled conditions to prevent reinfection.

Production and maintenance of G1 material must be in within the NCPN-FT system or equivalent program as approved by the department director.

(6) "G2" means plant material that is propagated from G1 stock and maintained by the certified nursery under the specific conditions outlined in this chapter to prevent (re)infection.

(7) "G3" means plant material that is propagated from G1 or G2 stock to increase the amount of source material available for producing virus-tested certified nursery stock. G3 plants must be maintained under the specific conditions outlined in this chapter to prevent (re)infection.

(8) "G4" means plant material that is propagated from G1, G2, or G3 stock that will be commercially distributed.

(9) "Index" means to determine virus infection by means of inoculation from the plant to be tested to an indicator plant or by any other scientifically acceptable means of detection.

(10) "Indicator plant" means any herbaceous or woody plant used to index or determine virus infection.

(11) "NCPN-FT" means the United States Department of Agriculture National Clean Plant Network for Fruit Trees.

(12) "Off-type" means different from the cultivar as stated on the application for certification.

(13) "Registered tree" means a tree or clonal planting that has a registration number assigned to it by the department, and that has been inspected and tested in accordance with the provisions of this chapter.

(14) "Scion block" means a planting of registered G2 or G3 trees, which serves as a source of scionwood for the propagation of Washington certified nursery stock.

(15) "Seed block" means a planting of registered G2 or G3 seed trees, which serves as a source of seed for producing rootstock used in the propagation of Washington certified nursery stock.

(16) "Stool bed" means a clonal planting of self-rooted registered G2 or G3 trees for the specific purpose of producing vegetatively propagated rootstock used in the propagation of Washington certified nursery stock.

(17) "Targeted" refers to harmful viruses and virus-like agents that cause diseases of commercial pome and stone fruit trees (plant genera Amelanchier, Chaenomeles, Cydonia, Crataegus, Malus, Prunus, Pyrus, and Sorbus) and that may be tested for as a condition of participation in the certification program.

(18) "Tested" means having been subjected to an official examination, other than visual, to determine if pests are present or to identify pests.

(19) "Tissue culture" means a general term for the cultivation of plants (cells, tissues, or organs) under aseptic conditions in a synthetic medium in vitro. It also refers to the cultures themselves.

(20) "Topworking" means the propagation by budding or grafting of scionwood onto a rootstock or established tree.

(21) "Virus" means virus and other graft-transmissible virus-like entities such as phytoplasma and viroids.

(22) "Virus infected" means the presence of a targeted virus in a plant or plant part.

(23) "Washington certified nursery stock" means G4 plant materials including nursery-grown seedlings, clonal root-stocks originating from registered G2 or G3 trees, nursery-grown trees propagated by using top-stock from registered G2 or G3 trees, and rootstock originating from registered G2 or G3 trees of the plant genera Amelanchier, Chaenomeles, Cydonia, Crataegus, Malus, Prunus, Pyrus, and Sorbus.

(24) "Washington certified seed" means seed produced on registered G1, G2, or G3 seed trees. It could also pertain to virus-tested seed from other sources approved by the department for production of G4 trees.

Certification by the department shall not imply or be construed as any warranty of the department or their employees as to the condition of nursery stock. The following requirements and conditions shall be met to qualify for consideration of certification of nursery stock:

(1) The applicant for certification shall be responsible for the selection of the location and the proper maintenance of all plantings being grown. The applicant shall also be responsible for maintaining the identity of all nursery stock. Any planting entered into this certification program shall be kept in a thrifty growing condition and actively managed for plant pests.

(2) Trees may be registered for certification as rootstock, interstock, and scion sources for the propagation of Washington certified nursery stock when inspected, tested, and found to be discernibly free from targeted viruses and having trueness to type, in accordance with the procedures prescribed in this chapter.

(3) No budding, grafting, or top-working of registered G2 and G3 trees in a scion block, seed block, or stool bed shall be permitted without prior permission from the department. Use of a certified G2 and G3 nursery stock (from another nursery) for scionwood shall only be allowed upon receiving permission from the department and shall be subject to departmental supervision.

(4) Registered scion and seed blocks will be maintained with insect management appropriate to mitigate risk of insect vectored viruses and virus-like organisms. Monitoring for insect vectors will occur during the growing season using best management practices defined by Washington State University. When presence of insect vectors is detected, insecticides and deterrents shall be employed to cover potential vector activity periods.

(5) Any plant found to be infected by a targeted virus and officially confirmed by the department, or in root or foliar contact with a confirmed infected plant, shall be removed immediately from any planting and destroyed after notification is provided by the department. For scion blocks, if a tree identified to be infected with a targeted pathogen remains into the following growing season, the department may decertify adjacent and nearby plants within the same block. The distance to which decertification occurs is dependent upon the risk factors of pathogen spread, but shall not be less than 10 feet. For stool beds, if an infected plant is present the following growing season, all plants growing within 10 feet of the infected plant will not be certified. Decertified plants may be recertified if department-approved corrective action is taken.

(6) Prior to planting, all registered plant growing areas and their contiguous border areas of not less than 10 feet, shall be tested for the presence of soil-inhabiting nematodes known to transmit any of the targeted viruses. Growing areas found free of nematode vectors will not require chemical fumigation. Growing areas found infested with nematode vectors are required to be fumigated in accordance with the rates and practices recommended by Washington State University. The growing areas will then be retested. Such tests and treatments shall be carried out under the supervision of the department.

(7) Applicants shall be responsible for maintaining trueness to type of certified G4 nursery stock produced from registered G2 and G3 plants. The applicant shall develop a written program, in cooperation with the department, so as to provide for monitoring of each cultivar for trueness to type. Trees found to be off-type shall be removed.

(8) The applicant must maintain, and when requested, provide to the department at no cost, the following records for all registered G2 and G3 nursery stock in this program for a minimum of 10 years:

(a) Records indicating the Latin name, variety or cultivar, rootstock, origin, date of introduction of the G1 or G2 plant materials to the facility, date of propagation in the registered G2 or G3 block, and field location including nursery row and block;

(b) Records of sale and copies of all phytosanitary certificates issued; and

(c) Maps of the facility or nursery indicating the growing areas and a detailed inventory for the registered G2 and G3 plants.

(1) The department will assign a registration number to each registered scion tree.

(2) Only registered G2 or G3 trees are permitted in a registered scion block.

(3) Isolation requirements. Prunus trees must be at least 100 feet from any nonregistered Prunus tree and any nonregistered members of the Rosaceae family.

(a) Plant genera Amelanchier,Chaenomeles, Cydonia, Crataegus, Malus, Pyrus, and Sorbus trees must be at least 60 feet from any nonregistered plant of the Rosaceae family.

(b) The department may waive the isolation distance for registered trees of these genera, if the trees are separated by a physical barrier that would prevent the intermingling of roots.

(c) The department may waive the isolation distances for registered tissue culture lines of these genera, if kept under sterile laboratory conditions or an indoor insect proof facility.

(4) The ground in a scion block and for a distance of 20 feet on all sides around it shall be kept clean cultivated or in grass (Gramineae) or another approved cover in which broad-leaved weeds are actively controlled.

(5) The rootstock and scion sources of the G2 and G3 scion-block trees shall have originated from G2 trees established under this certification program or from virus-tested G1 trees originating through the National Clean Plant Network-FT or other department-approved virus-tested sources. If the tree is scion-rooted, its source shall have met the above-mentioned requirements.

(6) Registered scion trees may be propagated with scionwood from other registered trees, if all of the following conditions are complied with:

(a) No registered tree utilized is more than two generations from the foundation source.

(b) The registered tree providing scionwood for a second-generation registered tree is identified and its location is known.

(c) The department monitors the propagation of second-generation registered scion trees.

(1) The department will assign a registration number to each registered seed tree.

(2) Prunus seed blocks must be located at least 100 feet from any nonregistered Prunus plants and any nonregistered member of the Rosaceae family.

(3) The ground in a seed block and for a distance of 20 feet surrounding the seed block shall be kept clean cultivated or in grass (Gramineae) or another approved cover in which broad-leaved weeds are actively controlled.

(4) The rootstock and scion sources of the seed tree shall have originated from G2 or G3 trees established under this program or from virus tested G1 trees originating through the NCPN-FT or other department-approved virus tested sources. If the tree is scion-rooted, its source shall have met the above requirements. Only registered trees shall be permitted in the seed block.

(1) Existing stool beds not found to be virus infected via testing approved by the department may qualify as registered G3 stool beds. New stool beds shall have originated from G2 or G3 stock established under this certification program, or from virus-tested G1 plants originating through the NCPN-FT or other department-approved virus-tested sources. Only registered plants shall be permitted in the registered stool bed.

(2) Registered stool beds must be at least ten feet from nonregistered plants of the Rosaceae family.

(3) Ground in a registered stool bed, and for a distance of at least 10 feet surrounding it, shall be kept clean cultivated.

(4) The isolation distance shall not apply to registered stool beds produced by aseptic micropropagation and maintained under sterile laboratory conditions or an indoor insect proof facility.

The following requirements specifically apply to scion blocks of containerized plant genera Amelanchier, Chaenomeles, Cydonia, Crataegus, Malus, Prunus, Pyrus, and Sorbus species:

(1) The roots of trees being containerized must be free of soil prior to planting in the containers;

(2) The growing medium must consist of nonsoil material including, but not limited to, expanded or baked clay pellets, ground coconut husks, coffee hulls, cocoa pods or rice husks, peat, perlite, sawdust, sphagnum, volcanic ash, cinder, or vermiculite. The components of the growing medium must not have been previously used for growing plants or other agricultural purposes. The components of the growing medium must be mixed and maintained under conditions which preclude soil contamination or contamination by water run-off. Samples of the growing medium may be taken to verify the absence of soil.

(3) The containers must be set on a barrier that prevents the roots of the plants from permeating the soil or prevents direct contact with the soil, such as plastic, hard-packed clay, pavement, or a minimum of two inches of coarse gravel. The site must be located so as to preclude soil contamination, either directly or through water run-off from drainage, flooding, irrigation, or other means.

(4) All other requirements for growing scion blocks must be met (see WAC 16-350-025).

(1) The following requirements apply specifically to tissue culture plant materials grown by organogenesis for scion and for rootstock:

(a) Plants (explants) used to produce callus for tissue culture must be tested or indexed annually.

(b) Plantlets (rooted shoots) regenerated from the tissue culture callus must be grown in a greenhouse or growth chamber and all measures and precautions must be taken to prevent the presence of any vectors in the greenhouse or growth chamber.

(c) One regeneration of plantlets from the tissue culture callus will be certified under this program as G4 level material with no further testing or indexing provided all other requirements are met. This certification will last one year from the date of introduction of the plantlets into the greenhouse. Plantlets may be planted as G3 level registered plants provided all other requirements, including testing, are met for scion and for stool beds.

(d) All other requirements for scion blocks and for stool beds must be met (see WAC 16-350-025 and 16-350-032).

(2) For tissue cultures originating through aseptic micropropagation, without callus formation, the following requirements apply:

(a) With the exception of practices allowed in (b) of this subsection, registered G2 trees must be propagated directly from virus-tested G1 plants originating through the National Clean Plant Network-FT or other department-approved virus-tested sources.

(b) Plants propagated from G1 material and maintained as G2 mother trees entirely under screenhouse conditions may serve as a source to establish a registered G2 tissue culture line. The source G2 mother trees shall be tested annually by the department.

(c) All other requirements for scion blocks and stool beds must be met (see WAC 16-350-025 and 16-350-032).

(3) Upon approval from the department, plantlets produced from registered G2 tissue culture lines may retain G2 status if placed in new commercial growing media and maintained in an indoor insect proof facility. Routine testing by the department as outlined in this chapter shall apply.

(4) All other G2 plantlets shall become G3 when planted in growing media and must meet the requirements of this chapter.

The following requirements specifically apply to Washington certified nursery stock, also known as G4 level material:

(1) The applicant must maintain, and when requested, provide to the department at no cost, the following records of all G4-level materials in this program for at least 10 years.

(a) Records indicating the Latin name, variety or cultivar, rootstock, origin, date of introduction of the G2 materials to the facility, date of propagation in the registered G2 or G3 block, and field location including nursery row and planting.

(b) Records of sale and copies of all phytosanitary certificates issued.

(c) Maps of the facility or nursery indicating locations of Washington certified nursery stock.

(2) All nursery stock grown for G4 certification shall be on rootstocks from registered G2 or G3 trees, except for stone fruit trees grown on peach seedlings from qualified seed sources. Prunus root-stocks for G4 certification shall be acceptable only if the seed transmissible virus content does not exceed five percent and as approved by the department. Clonal rootstocks used in the production of Washington certified nursery stock shall originate from registered stool beds or department-approved certification programs from other states.

(3) Nursery stock grown for G4 certification shall be planted sufficiently apart to maintain its identity and shall be kept clean-cultivated. Such nursery stock shall be designated as to rootstock, top-stock, and interstock sources. Rebudding or regrafting of nursery row stock shall not be allowed unless such stock is reworked with budwood from the same registered scion block.

(4) Seed may be designated as Washington certified seed only if both of the following conditions are complied with:

(a) The seed was produced on registered seed trees; and

(b) The seed lot has been tested for transmissible virus content, and not more than five percent of the seed tested positive for transmissible viruses.

(5) Official certification tags approved by the department may be attached to bundles of G4-level trees at time of distribution and documentation of certification can also be supplied with the invoice.

(6) When it is offered for sale, Washington certified nursery stock must be identified as to variety, interstock and rootstock.

(1) Inspection and testing procedures prescribed in this certification program may be carried out by the department, and shall be conducted at such times and in such manner as is acceptable to the department.

(2) The methods and procedures used for virus indexing and testing shall conform to NCPN-FT or department-approved standards.

(3) The department reserves the right to visually inspect and test nursery rootstock in a planting for certification throughout the growing season. At the request of the department, any undesirable rootstock must be rogued before propagation.

(4) Any person selling, or offering for sale, any nursery stock or seed identified by tagging as Washington certified nursery stock shall be deemed to be responsible for the identity of such stock. All Washington certified nursery stock offered for sale shall be handled in accordance with accepted commercial practices and shall be identified by the tags described in WAC 16-350-050.

(5) The department will refuse certification of planting stock that has been propagated from registered trees found to be virus-infected or if other requirements of this chapter have not been met.

(6) A list of participating nurseries and certified nursery stock shall be provided to all participating nurseries and to other interested parties upon request.

(7) The department accepts certified material from other states with an approved certification program.

(1) In addition to visual inspections conducted twice annually, all registered G2/G3 trees may be subject to diagnostic assays to determine the presence of targeted pests listed under this section.

(2) Testing will be prioritized as follows:

(a) Symptomatic G2/G3 trees will be tested immediately by the department.

(b) As funding allows, registered G2/G3 Prunus trees shall be tested by the department on a three-year rotation for Little Cherry Virus 1, Little Cherry Virus 2, Western X phytoplasma, Prune Dwarf Virus, Prunus Necrotic Ringspot Virus, and Cherry Leaf Roll Virus. Registered Prunus trees without testing in the previous 36 months shall not be used for budwood for production of certified trees.

(3) The department and entities authorized by the department will test registered G2/G3 trees by methods consistent with those utilized by the NCPN-FT or department-approved standards.

(4) G2/G3 trees may be tested for the following targeted pests if symptomatic for disease:

(a) Pome fruit:

(i) Apple mosaic virus;

(ii) Apple chlorotic leaf spot virus;

(iii) Apple stem pitting virus;

(iv) Apple green crinkle associated virus;

(v) Apple stem grooving virus;

(vi) Apple rubbery wood virus-1;

(vii) Apple rubbery wood virus-2;

(viii) Apple luteo virus-1;

(ix) Apple scar skin viroid;

(x) Pear blister canker viroid;

(xi) Cherry rasp leaf virus;

(xii) Citrus concave gum-associated virus;

(xiii) Tomato ringspot virus;

(xiv) Tobacco ringspot virus;

(xv) Generic phytoplasma;

(b) Stone fruit:

(i) Apple mosaic virus;

(ii) Apple chlorotic leaf spot virus;

(iii) Arabis mosaic virus;

(iv) Cherry mottle leaf virus;

(v) Cherry green ring mottle associated virus;

(vi) Cherry necrotic rusty mottle virus;

(vii) Cherry rusty mottle associated virus;

(viii) Cherry rasp leaf virus;

(ix) Cherry leaf roll virus;

(x) Generic phytoplasma;

(xi) Candidatus phytoplasma pruni (X-Phytoplasma);

(xii) Hop stunt viroid;

(xiii) Little cherry virus-1;

(xiv) Little cherry virus-2;

(xv) Prune dwarf virus;

(xvi) Prunus necrotic ringspot virus;

(xvii) Plum pox virus;

(xviii) Tomato ringspot virus;

(xix) Tobacco ringspot virus;

(xx) Nectarine virus M;

(xxi) Nectarine stem pitting-associated virus;

(xxii) Plum bark necrosis stem pitting associated virus;

(xxiii) Peach mosaic virus;

(xxiv) Peach latent mosaic viroid;

(xxv) Xylella fastidiosa.

(1) The applicant must provide the department with all information documenting the eligibility of all registered and certified stock and must allow the department to take samples for indexing or testing purposes.

(2) An application for certification must be filed with the department by June 1 of each year accompanied by an application fee. The application fee will consist of $100.00 plus $10.00 for each registered Prunus tree and $2.00 for each registered pome tree.

(3) The application fee will apply toward the annual assessment on the gross wholesale price of all fruit trees and fruit tree related ornamental nursery stock produced in Washington and sold within the state or shipped from the state during any license period, as set forth in RCW 15.13.310. No refund of the application fee will be allowed.

(1) The department authorizes the use of official certification tags for the identification of nursery stock or seed that meet the requirements of this program. Official standards for the tags will be provided to participating nurseries for printing. Certification tags must be approved by the department prior to use.

(2) Any person selling Washington certified nursery stock or Washington certified seed is responsible for the identity of the stock bearing each tag and for such nursery stock or seed meeting the requirements of this program. Persons issued tags authorized by the program must account for stock produced and sold, keep such records, and make them available at no cost to the department upon request.