Organisations participant

     Instituto Valenciano de Investigaciones Agrarias (IVIA). Departamento de Protección Vegetal y Biotecnología. Moncada, Valencia, Spain.

     Consellería d’Agricultura i Pesca (CAP). Dirección General de Innovación Agraria y Ganadería. Servicio de Viticultura y Enología. Requena, Valencia, Spain

Financial resources

    Ministerio de Ciencia y Tecnología (MCT). National Programme of Feeding. Strategic action “Improvement of quality and competitiveness of the vines”: Project num. VIN01-034-C2-1.

First phase of the project

    Period that includes the years 2002, 2003 and 2004.

    The esca of grapevine (Vitis vinifera L.) may be as old as vine cultivation itself. Symptomatologies that evoke this disease are indicated in several ancient Greek and Rome works. Spain - one of the countries with more superficie of vineyards (1100000 Ha. ) -  confirm the presence of esca in the 1898, when an agricultural specialist sends samples of decayed wood to VIALA from vineyards of the Valencia province. At present, the esca diffussion through the country reachs all grape-growing areas and causes appreciable injuries. In the Spanish mediterranean area, principally in the Comunidad Valenciana with a superficie of vineyards of  86200 Ha. and a great care in the cultural practices,  this wood disease is very preocupant by the number of affected vines for two decades. Both the aggressive climatic conditons (rainfalls lesser of 300 lt/m2, low atmosferic humidity during long periods of the year, marked alternations of heat and could) and the cultural practices (no irrigation in the majority of the vineyards, severe prunings and frequents nitrogen amendments) existing in this Spanish area clearly exercise together as persistant predisposition factors in the host-fungal pathogens relation what makes possible variations in the activity of the several fungi that participate in the development of esca. It force us to reconsiderer the pathology of this disease and to study in depth the complex etiology of esca in the refered geografical area.

    The goal of this project is the study of the fungi (taxonomy and pathogenicity) causing of esca - a chronic and importat diasease of grapevines- in the Spanish mediterranean climatic conditions as well as the possibility of an integrated control.

    In vineyards previously picked for its age, geografic situation and cultivar intensive carry out studies of the different symptoms expressed by the esca. Identical in mother vines (rootstocks) nurseries and grafted young vines.

    In symptomatic vines, isolation of the several fungi from mycelium into wood and from fruiting bodies (in this case for the basidiomycetes exclusively). Morphological identification and, in determined cases, by restriction fragment length polymorphism analysis (RLSP). Maintaining of a collection of the isolated and purificated fungi.

    In laboratory: proofs the wood decay ability using small segments of grapevine wood. In glasshouse: observation of internal symptoms by means of inoculation in vine shoots (canes) of the several grapevine cultivars. In the field: planting health young vines grafted of several vultivars in the proximity of diseaded adults vines and these young vines intensively observed and studied for the detection of the fungi associated to esca.

    Chemical control both in the laboratory (direct confrontation between chemical and fungus in the petri dishes) an in the field using several broad-spectrum fungicides. Biological control with antogonists. Improve of traditional cultural methods including: the employment of health propagative material, adequate cultural practices, reasoned prunings, etc.

    The studies were carried out during the period april-november 2002, coinciding with the vegetative cycle of the vines, in several vineyards, all them spreaded in the wine and table grape-growing areas of major importance of the Comunidad Valenciana (provinces of Valencia and Alicante) (Fig.1).

     

    The samples were obtained from adult vines (more 20 years old) with charecteristic esca syndrome, and also of the asymptomatic vines. Some samples were also achieved  from young vines (1 to 4 years old) with wood decay and decline symptoms.

    Five cultivars for wine: Garnacha, Bobal, Monastrell, Tempranillo and Merseguera, and three for table: Moscatel, Italia and Alfonso Lavallé have been sampled. The samples were composed by canes (vine shoots), larger branches (arms) and trunks of vines of these cultivars with variable symptoms of disease, specially on the leaves (Fig.2). The number of samples in this first year was 32 (27 from adult vines and 5 from young vines). In the laboratory this material was processed and carefully analysed: external and internals symptoms, fungi isolations from the symptomatic and asymptomatic tissues, etc.

     

    During year 2002 the temperature (T), rainfall (R) and relative humidity (RH) at wine and table grape growing areas in Comunidad Valenciana have been:

    In Table 1 is given of the fungal species that have been isolated, frequencies at wich they ocurred, associated symptoms, organs from which they have been isolated.

Table 1.- Wood decay fungi of the grapevine isolated from 32 samples during the period april-november 2002 in Comunidad Valenciana.

    These fungi isolated from adult vines only. In the young vines no wood fungi has been isolated. D.mutila (Tel. B.obtusa) and S.hirsutum have been regularly isolated in the majority of these vine samples (Fig. 3 and 4). P.chlamydospora and P.aleophilum, although in minor rate, have been also isolated with relative facility as well as P.viticola, fungus causing of “ dead arm” disease. P.eupyrena has been normally isolated from vines with un avanced decay (spongy tissues) and possibly has a low pathogenic capacity. It is the first record of this fungus in Spain.

     

    Several researchs on the isolated fungi concerning the typus of cultural media (Fig. 5), optimal temperature of growth and “in vitro” formation of fruiting bodies (for basidiomycetes) have been also undertook.

     

    An initial research to control of P.chlamydospora using several isolates of Chaetomium sp., both  in vitro and in vivo, in this case emploing portions of young vine canes, it is current being studied for us (Fig. 6). Chaetomium migth be an interesting antagonist of  P.chlamydospora in the wound sites such as pruning or grafting.

     

    During this year the research of esca will be focused on:

    1.- Surveys in affected vineyards and nurseries. Isolations of wood decay fungi.
    2.- To clarify the pathogenic activity (recurring the wood decay symptoms) of these fungi (specially of Mytosporic species) on major wine and table grapevine cultivars in greenhouse.
    3.- Implantation of several plots composed by health young vines of these grapevine cultivars intermingled with affected vines to study the mode of spread of these fungi as well as the contamination process and to start the possibilities of esca control with emploing cultural and chemical methods.
    4.- To continue with the biological control at laboratory, greenhouse and field.