EuropeanBlackwell Publishing Ltd and Mediterranean Plant Protection Organization PM 4/34 (1) Organisation Européenne et Méditerranéenne pour la Protection des Plantes Schemes for the production of healthy plants for planting Schémas pour la production de végétaux sains destinés à la plantation Production of pathogen-tested herbaceous ornamentals Specific scope Specific approval and amendment This standard describes the production of pathogen-tested First approved in 2007-09. material of herbaceous ornamental plants produced in glasshouse. This standard initially presents a generalized description of the 2. Maintenance and testing of candidate plants performance of a propagation scheme for the production of for nuclear stock pathogen tested plants and then, in the appendices, presents details of the ornamental plants for which it can be used 2.1 Growing conditions together with lists of pathogens of concern and recommended test methods. The performance of this scheme follows the general The candidate plants for nuclear stock should be kept ‘in sequence proposed by the EPPO Panel on Certification of quarantine’, that is, in an isolated, suitably designed, aphid-proof Pathogen-tested Ornamentals and adopted by EPPO Council house, separately from the nuclear stock and other material, (OEPP/EPPO, 1991). According to this sequence, all plant where it can be observed and tested. All plants should be grown material that is finally sold derives from an individual nuclear in individual pots containing new or sterilized growing medium stock plant that has been carefully selected and rigorously that are physically separated from each other to prevent any tested to ensure the highest practical health status; thereafter, direct contact between plants, with precautions against infection the nuclear stock plants and the propagation stock plants by pests. derived from it are maintained under controlled conditions in glasshouses to limit the risk of any infection. 2.2 Testing requirements All candidate plants should be individually tested for the major 1. Selection of candidate plants and minor pathogens specified in the appropriate Appendix for The candidate material may be new cultivars, good-quality the plant concerned where recommended test methods for these material of existing cultivars, tissue cultures or meristem-tip pathogens are given. cultures of any of these. Material originating from outside In general testing of plants on indicator plants is recom- the EPPO region should also be inspected for all EPPO-listed mended because this will act as a general screen for viruses that pests1 and tested under quarantine for all EPPO-listed pests can be transmitted by sap (mechanically). In addition, when of the crop concerned occurring in the region of origin, and candidate plants may have been in contact with soil or soil water generally inspected for any other pests. Inspections and (e.g. originate from open-field cultivation), they should also be tests should be performed according to the relevant EPPO screened for Nepoviruses and Tobraviruses (using either Nicotiana phytosanitary procedures. occidentalis or N. benthaminia, and Chenopodium quinoa). The plants should be visually inspected regularly for all pests. When plants are grown in soil, the soil should be free of vector nematodes. Apart from the vector pests which can be adequately controlled (e.g. aphids, Frankliniella occidentalis 1EPPO-listed pests are pests listed in EPPO Standard PM 1/2 EPPO A1 and and Bemisia tabaci), any plant found to be infected, by testing A2 Lists of pests recommended for regulation as quarantine pests. or by visual examination, should be immediately eliminated. © 2008 OEPP/EPPO, Bulletin OEPP/EPPO Bulletin 38, 31–52 31 32 Schemes for the production of healthy plants for planting The same applies to plants transferred from in vitro culture to 2.3 Promotion to nuclear stock pots. In general, a regular control of trueness to type is also The plants that give negative results in all tests and inspections necessary when maintaining material in vivo or in vitro. can be used to produce nuclear stock plants; depending on the crop, this can be by direct transfer of the tested plant to nuclear 3.3 Authorization stock conditions or by propagation by tissue culture, cuttings, bulbs, tubers etc. Promotion to nuclear stock and transfer to the Before a nuclear stock plant may be propagated further in the nuclear stock conditions can only occur following verification scheme, the passage of propagating material to the next stage and authorization that all required tests and observations have should be authorized on the basis of records of the tests and been performed with negative results. This scheme may be used observations performed during production, and of one or more to establish an official certification scheme. In case of an official authorization (visual) inspections. At inspection, the nuclear certification scheme the certifying authority monitors this stock plant should show no symptoms of fungal, bacterial and process. viral diseases (unless they can be adequately controlled), and should be free of vector insects (e.g. aphids or thrips), otherwise the plant should be refused. If propagating material from nuclear 3. Maintenance and testing of the nuclear stock stock leaves the scheme, it can be referred to as ‘pre-basic’ material (provided this has been officially authorized). 3.1 Growing conditions For some crops, the nuclear stock can be maintained in vitro 4. Propagation stock I and, in this form, the clones derived from these individual plants will retain the same status in the scheme. Otherwise, 4.1 Growing conditions in vivo nuclear-stock plants should be kept in a suitably designed aphid-proof house, containing only nuclear-stock plants. They Cuttings, or other plant parts used for propagation depending should be maintained under the same conditions, and with the on the crop, taken from the nuclear-stock plants when planted same precautions against infection as candidate nuclear-stock become propagation stock I. plants (see point 2 above). A check on trueness to type should The plants should be kept in isolated houses, separate from be made; for many ornamental crops this is done by bringing any other plants that are not at an equivalent stage of a similar either the nuclear stock plants, or cuttings/bulbs taken from scheme. Plants should be grown either in individual containers them, to flower, but the flowering may need to be done in a or in a system of small growing units ensuring adequate isola- different place to avoid risk of infection. tion. General precautions against pests should be maintained. The useful life of a nuclear-stock plant is generally limited by The number of generations of propagation stock I that should the longevity of the individual plants of the species. In other cases, not be exceeded and the useful life of a propagation stock I plant because of the risk of re-infection, the in vivo nuclear stock plants are indicated in the Appendix for the plant concerned. After should be re-tested after the period of time as specified in the this period all the propagation-stock I plants should either be appropriate Appendix for the plant concerned. In addition, when retested or replaced by new plants. The filiation of the plants maintenance is done in vitro, retesting is recommended. should be recorded, so that each lot is known to be derived from nuclear stock by not more than the fixed number of generations of propagation under the required conditions. 3.2 Testing requirements Throughout the production of propagation stock I, checks All plants should be individually tested for the pathogens should be made on varietal purity and on possible mutations or specified in the appropriate Appendix for the plant concerned at back mutations. least once during the productive life of the plant. The frequency of testing should reflect the risk of infection and how long the 4.2 Testing requirements nuclear stock plants are kept. Appropriate control measures should be applied to control The minimum requirements for Propagation stock I plants are the other pests specified in the Appendix for the plant concerned. given in the Appendix for the plant concerned together with the The plants should be visually inspected at regular intervals for recommended tests methods for these pathogens. At this stage all pests. Any plant showing infestation should be eliminated. of the scheme, the testing requirement is commonly random Plants propagated from nuclear-stock plants can also be testing of lots or (sub-lots) of propagation-stock I plants, or considered as nuclear stock, provided that they do not leave the visual inspection for specific symptoms. Any plant giving a nuclear stock conditions2 and are individually tested as above. positive result at random testing should be eliminated and recorded. In the case of a positive test result, all plants in the group of plants from which the sample was taken (whole lot 2They may be transferred to other, similar, nuclear stock conditions and still retain nuclear stock status provided that they are transported while or sub-unit) should be tested individually. All positive plants packed at all times in suitable containers designed to avoid contamination should be eliminated. The plants should be visually inspected (e.g. aphid-proof ). regularly for the presence of any pest. Any plant found to be © 2008 OEPP/EPPO, Bulletin OEPP/EPPO Bulletin 38, 31–52 Production of pathogen-tested herbaceous ornamentals 33 substantially infested by any pest should be eliminated, except be given in the Appendix for the plant concerned. General in the case of pests which can be adequately controlled. precautions against pests should be maintained. An effective crop protection program should be in place. The number of generations of propagation stock II that should 4.3 Authorization not be exceeded and the useful life of a propagation stock II Authorization for further propagation will be granted on the plant are indicated for each crop in the relevant appendix.