Organic cider-apple production in Asturias (NW Spain)

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1 Integrated Fruit Protection in Fruit Crops IOBC wprs Bulletin Vol. 28 (7) 2005 pp Organic cider-apple production in Asturias (NW Spain) Enrique Dapena, Marcos Miñarro, María Dolores Blázquez Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Apdo. 13, E , Villaviciosa, Asturias, Spain, enriquedf@serida.org. Abstract: Cider is a key economic factor in the Asturian (NW Spain) agrarian sector, where apple production is principally geared towards cider making. Research on sustainable strategies for managing cider-apple orchards has been performed by the SERIDA since Nowadays, a viable strategy for organic cider-apple production may be recommended. Cultivar selection is of critical importance in the planning of new orchards. In organic production, disease and pest susceptibility is an important consideration. The cultivars selected by SERIDA are highly recommended because of their disease tolerance, productivity and juice quality. Recently, some cultivars resistant to both scab and the rosy apple aphid have been obtained in a breeding programme. Since recommended cultivars are tolerant to fungi, their selection makes the use of fungicides normally unnecessary. Thus, phytosanitary sprays are reduced to those used against the codling moth (granulosis virus) and the rosy apple aphid (neem-based insecticides). Other potential pests are regulated naturally or do not represent a serious problem for cider-apple production. A semi-intensive to semi-extensive system with trees growing on semi-dwarfing rootstocks (M.7, MM.106, MM.111) or even seedling rootstocks in markedly sloping sites) has been chosen because trees may be grown without irrigation and trunk support in most cases. Trees are developed in vertical-axis or sole-axe systems. The proper fertilization of trees is achieved with applications of organic fertilizers and/or composted cow-manure. Weed competition in the tree row is suppressed by mulching (grass, straw, pine-bark) or mechanically. Fruit thinning is done by hand (extinction technical or by removing fruits manually). Apples may be marketed individually or collectively, dealing directly with the cider producer. Apples produced under organic conditions reach a higher price than conventionally produced apples. Organic cider-apple production is possible when the orchard is well planned and managed in a holistic manner. Growing of resistant cultivars is a key factor in achieving success. This system is applicable to dessert-apple production with some minor adaptations (e.g. tree vigour or the planting system) when scab-resistant cultivars are grown. Key words: bottom-up approach, cider-apple, organic production, resistant cultivars, semi-intensive system Introduction Cider is a traditional valuable feature and a key economical factor in Asturian (NW Spain) (43 N, 5 W) agrarian production. Thus, apple production is almost exclusively geared towards cider making. Research on sustainable strategies for managing cider-apple orchards has been performed by the SERIDA (Servicio Regional de Investigación y Desarrollo Agroalimentario) since 1986 (Dapena & Blázquez, 2002). This research allows us to recommend a viable strategy for organic apple production which is being adopted by a rising number of growers. The change from conventional to sustainable fruit production has usually been done under a top-down approach, i.e. starting with a conventionally-managed orchard and reducing progressively the external inputs while ecological processes of natural control are gradually established. However, a bottom-up approach is possible (Prokopy, 2003). This bottom-up approach is based on a suitable design of the plantation, a correct habitat

2 management, and a management of pests and diseases based on the growing of resistant rootstocks and cultivars, cultural management and biological control (Prokopy, 2003). Organic production (Weibel & Häseli, 2003) as well as the IOBC (Cross, 2002; Avilla & Riedl, 2003) greatly recommend the adoption of the bottom-up approach. The SERIDA also adopted this approach for research and production of cider-apples. A semi-intensive to semi-extensive system In order to take advantage from both traditional extensive and conventional intensive systems of production, a semi-intensive to semi-extensive system has been adopted for producing cider-apples in Asturias (Dapena et al., 2002). This system is based on the growing of trees on semi-dwarfing rootstocks (M.7 and MM.106 with vigorous cultivars and MM.111 with cultivars of moderate vigour) with a tree-density of trees/ha. MM.111 (550 trees/ha) and seedling rootstocks (220 trees/ha) are used in sites with marked slope. The elevated vigour and height reached by trees are not a handicap for cider-apple production since apples are harvested on the ground. The most important advantage of this system vs. intensive production is the few requirements derived from the greater vigour. Irrigation and trunk support are unnecessary in most of the cases and the inputs into the orchard are lower. The main advantage vs. traditional big trees is the easier management of trees (i.e. pruning, spraying). Trees are formed in vertical-axis or sole-axe system taking into consideration the natural growing habits of each cultivar. Cultivars A proper choice of cultivars is of critical importance in the planning of new orchards. Apart from productivity and the technological and organoleptical features of the apples, resistance to pests and diseases should be a key point in the choice of cultivars for a sustainable production (Cross, 2002; McCarthy, 1994; Avilla & Riedl, 2003; Prokopy, 2003; Weibel & Häseli, 2003). Disease and pest susceptibility is an important consideration especially in organic production, where alternative methods to chemicals are usually less effective and more expensive. A group of Asturian cultivars with high productivity, juice quality and resistance or little susceptibility to scab, powdery mildew, European canker and monilia have been selected by SERIDA: e.g. De la Riega, Durona de Tresali, Raxao, San Roqueña, Solarina or Xuanina (Dapena & Blázquez, 2002). These cultivars are nowadays among the 22 cultivars accepted in the quality label Denominación de Origen Protegida Sidra de Asturias and all the apple growers who carry out a new orchard use these cultivars. Four to six cultivars are normally grown in a 1-ha orchard. Apart from these traditional cultivars, some hybrids resistant to both scab and the rosy apple aphid (Dapena & Blázquez, 2004; Miñarro & Dapena, 2004) have been obtained in a breeding programme in the SERIDA and are currently in registration process. They will be available for growers soon. Fertilization and groundcover management A proper fertilization of trees is achieved with organic fertilizers and/or composted cowmanure. Weed competition for water and nutrients in the tree row is avoided by mulching (grass, straw, pine-bark) or mechanically with a disc plough or a rotovator. The grass- and the

3 straw-mulches favour the soil humidity and the tree growth but may be a disadvantage with high densities of voles. Alleys are cleaned when necessary using a shredder. Fruit thinning Biennial bearing is a basic problem for both apple-growers and cider-producers in Asturias. 50,000 tons of cider-apple are produced in the on years while only 10,000 tons are produced in the off years. This is mainly a consequence of the bearing habits of these cultivars and is a problem for both organic and conventional production. Fruit thinning is made by manual removing of fruits. A new technical named extinction (Lauri et al., 2000) consisting of a partial removing of complete fruit points at stage D-E is also recommended (Díaz & Dapena, 2004). However, both methods require high labour and are difficult to carry out in big commercial orchards. Thus, research on thinning products compatible with organic production has been initiated. Management of pests and diseases Asturias has a humid climate in which fungi are the main phytosanitary problem. However, the growing of these cider-apple cultivars resistant to diseases allows an apple production free of fungicides. The risk of phytophthora crown and root rot is lowered by cleaning the herbs around the tree trunk. Fire blight has not been detected in Asturias. Among arthropods, only the codling moth and the rosy apple aphid are serious problems for cider-apple production in Asturias. Codling moth control is successfully achieved with the granulosis virus: damage is reduced up to less than 2 % with 6-8 sprays (Miñarro & Dapena, 2000). Mating disruption efficacy in Asturias is low, probably due to the small size of the orchards as well as the abundance of isolated trees or semi-abandoned orchards which act as infestation sources of mated females (Miñarro & Dapena, 2000). The rosy apple aphid may be controlled combining the use of tolerant cultivars, biological control and the spray of neemderived insecticides (Miñarro & Dapena, this volume). Other potential pests are regulated naturally or do not represent such a serious problem for cider-apple production to require an action plain: e.g. the European red mite is controlled by phytoseiid mites (Miñarro et al., 2002). The green apple aphid is generally not a problem which is easily eliminated with Rotenone sprays when necessary. Therefore, the only sprays to produce organic cider-apples in Asturias are those of granulosis virus against the codling moth and those of neem-derived insecticides against the rosy apple aphid when necessary. Voles (Arvicola terrestris, Microtus lusitanicus, M. agrestis) are an increasing problem in Asturian orchards. Trapping and a proper management of the groundcover can contribute to reduce damage. Research on this topic has been recently initiated in the SERIDA. Marketability There are few cider producers interested on elaborating organic cider or other derived products (e.g. juices, vinegar). Apples may be marketed individually or collectively, dealing directly with these producers. Apples produced under organic conditions reach a 10% higher price than apples produced under the quality label D.O.P. Sidra de Asturias, and a 25-30% higher price than conventionally produced apples. This can compensate the higher price of products and the extra labour demand. Production of organic dessert-apple

4 The system presented for cider-apple production is applicable to dessert-apple production in Asturias or in other pome production regions. Two possible difficulties to manage dessertapple orchards could be firstly the selection of appropriate cultivars and secondly the need of limiting tree vigour and height in order to allow an easy collection of fruit. Nowadays a lot of scab-resistant cultivars are available (Crosby et al. 1992; Brown & Maloney, 2003), some of which are also tolerant to the rosy apple aphid (Miñarro & Dapena, 2005). Moreover, other minor pests whose aesthetic damage is not a difficulty for cider-apples may become a problem for dessert-apples. Organic apple production in Asturias Constituted in 1986, the Council for Organic Production in Asturias registers and certifies organic producers. Nowadays, only 20 cider-apple producers are registered in this Council, although the number is increasing. Four organic-cider producers are also registered in Asturias. Conclusions This work shows that organic production of cider-apples is possible when the orchard is well planned and managed in a holistic manner. The growing of resistant cultivars is a key point for the success of the bottom-up approach. However, further research (e.g. alternatives to hand thinning) is needed. Most of the strategies presented to produce organic cider-apples could be translated to organic dessert-apple production with minor adaptations and even to conventional cider-apple production. Acknowledgements We thank F. Weibel for critical comments on the manuscript. This research was partially financed by the project INIA RTA C2. References Avilla, J. & Riedl, H. 2003: Integrated fruit production for apples-principles and guidelines. In: D.C Ferree & I.J. Warrington (eds). Apples: Botany, Production and Uses. (pp ). CABI Publishing, Oxon, UK. Brown, S.K. & Maloney, K.E., 2003: Genetic improvement of apple: breeding, markers, mapping and biotechnology. En: D.C. Ferree & I.J. Warrington (eds.). Apples: Botany, Production and Uses. (pp ). CAB International. Crosby, J.A., Janick, J., Pecknold, P.C., Korban, S.S., O Connon, P.A., Ries, S.M., Goffreda, J. & Voordeckers, A., 1992: Breeding apples for scab resistance: Fruit Var. J. 46 (3): Cross, J.V. 2002: Guidelines for integrated management of pome fruits in Europe. IOBC/wprs Bull. 25 (8): 45 pp. Dapena, E., & Blázquez, M.D. 2002: Conservación, evaluación, selección y mejora de los recursos fitogenéticos del Banco de Germoplasma de Manzano del SERIDA. Frutic. Profes. 128: Dapena, E., Blázquez, M.D. & Miñarro, M. 2002: El cultivo ecológico del manzano. In: J. Labrador, J.L. Porcuna & A. Bello (eds.) Manual de Agricultura y Ganadería Ecológica. (pp ). EUMEDIA- SEAE. Dapena, E. & Blázquez, M.D. 2004: Improvement of the resistance to scab, rosy apple aphid and fire blight in a breeding programme of cider apple cultivars. Acta Horticulturae: in press. Díaz, J.A. & Dapena, E. 2004: Regulación de la producción en cultivo ecológico de manzana de sidra. In: J. Tello (ed.) Libro de Actas del VI Congreso de la Sociedad Española de Agricultura Ecológica, Lauri, P.E., Kelner, J.J., Delort, F., Fouilhaux, L., Lespinasse, J.M., Laurens, F. & Belouin, A. 2000: Conduite

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