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Nematodes and Soil Ecology – Management of Plant-parasitic Nematodes in Vineyards

Howard Ferris

Department of Entomology and Nematology, University of California Davis, Davis, California, USA (hferris@ucdavis.edu; http://plpnemweb.ucdavis.edu/Nemaplex).

The soil is inhabited by many forms of nematodes; while some are important parasites of plants, many contribute to beneficial functions of the soil food web. Grape vineyards throughout the world are infested with many of the same species of plant-parasitic nematodes. In many cases, the nematodes are not native to the local area but have been introduced with planting stock, which highlights the challenge of producing nematode-free stock and underscores the need for planting material to be inspected and certified free of damaging nematode species.
Plant-parasitic nematodes feed on plant roots as ectoparasites or as endoparasites.

The soil is inhabited by many forms of nematodes; while some are important parasites of plants, many contribute to beneficial functions of the soil food web. Grape vineyards throughout the world are infested with many of the same species of plant-parasitic nematodes. In many cases, the nematodes are not native to the local area but have been introduced with planting stock, which highlights the challenge of producing nematode-free stock and underscores the need for planting material to be inspected and certified free of damaging nematode species.
Plant-parasitic nematodes feed on plant roots as ectoparasites or as endoparasites. Ectoparasites have greater exposure to natural enemies on the root surface and to management strategies while endoparasites, within the roots, have evolved sophisticated relationships with the plant host or mechanisms for avoiding plant defenses. The level of nematode damage to plants is reduced by avoidance or disinfestation of infested areas, minimizing the probability of re-infestation, the use of rootstocks with resistance or tolerance to damage by the nematode species present, and by maintaining a healthy and biologically active soil food web. The use of rootstocks provides the benefit of combining pest-resistance characteristics with the horticultural desirability of the scion.
Sources of resistance to many plantfeeding nematodes have been identified; often they are in different species of Vitis which requires considerable effort in crossing and selection. However, the resistance of rootstock selections to various nematode species has been determined. Maintaining reduced levels of plant-parasitic nematodes after vineyard establishment has been approached with two strategies: the use of non-phytotoxic chemical nematicdes and stewardship of the soil to maintain natural enemies of parasitic species and other desirable functions of the soil food web. The two strategies are generally incompatible because the nematicides affect a broader spectrum of organisms than just parasitic species of nematodes. Nematicidal chemicals with downwardlytranslocated systemic activity within the plant, which would preferably affect only nematodes attempting to feed on the roots and not the entire biology of the rhizosphere, would offer the greatest compatibility for the two approaches.
Stewardship of the soil food web requires the continuous or frequent provision of sources of carbon and energy to the soil ecosystem while maintain relatively undisturbed conditions. Sources of carbon and energy may be provided by organic amendments and by the use of cover crops that are non-hosts to nematode species of concern. Conventional management practices that involve large amounts of chemical fertilizer, pesticides and soil tillage have seriously decimated the assemblages of beneficial organisms that constitute the soil food web. Management strategies should be designed to reverse these detrimental effects and to rebuild healthy and biologicallyfunctional soils.

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In accordance with the Organic Law on the Protection of Personal Data 15/1999, of 13 December, Promotora de Exportaciones Catalanas SA (hereinafter PRODECA), whose address is Gran Via de les Corts Catalanes, 620, principal, 08007 Barcelona, with tax reg. no. NIF A58241316, declares that the images contained on the website www.smartfruitcongress.cat are included in a file belonging to PRODECA. The purpose of this file is the promotion, via its website, of the activities conducted by PRODECA – SmartfFruit IPM International Congress.

PRODECA guarantees that you may, at any time, exercise your right to access, rectify, cancel or oppose by writing to the aforesaid postal address, using the reference "PROTECCIÓN DE DATOS - SMARTFRUIT", or to the email address smartfruitcongress@smartfruitcongress.cat.

Specifically, to correctly exercise these rights you must clearly provide the following items in that communication:
- Name, surname(s) and photocopy of National Identity Document or Passport.
- Statement of the purpose of the request.
- Address for notification purposes.
PRODECA also declares that it reserves the right to delete from its website any content that it considers violates current and applicable legislation.

D’acord amb l’article 17.1 de la Llei 19/2014, la ©Generalitat de Catalunya permet la reutilització dels continguts i de les dades sempre que se'n citi la font i la data d'actualització i que no es desnaturalitzi la informació (article 8 de la Llei 37/2007) i també que no es contradigui amb una llicència específica.