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After replanting apple (Malus domestica Borkh.) on the same site severe growth suppressions, and a decline in yield and fruit quality are observed in all apple producing areas worldwide. The causes of this complex phenomenon, called apple replant disease (ARD), are only poorly understood up to now which is in part due to inconsistencies in terms and methodologies. Therefore we suggest the following definition for ARD: ARD describes a harmfully disturbed physiological and morphological reaction of apple plants to soils that faced alterations in their (micro-) biome due to the previous apple cultures. The underlying interactions likely have multiple causes that extend beyond common analytical tools in microbial ecology. They are influenced by soil properties, faunal vectors, and trophic cascades, with genotype-specific effects on plant secondary metabolism, particularly phytoalexin biosynthesis. Yet, emerging tools allow to unravel the soil and rhizosphere (micro-) biome, to characterize alterations of habitat quality, and to decipher the plant reactions. Thereby, deep insights into the reactions taking place at the root rhizosphere interface will be gained. Counteractions are suggested, taking into account that culture management should emphasize on improving soil microbial and faunal diversity as well as habitat quality rather than focus on soil disinfection.

The report presents the relevant genera and species known to cause damage to apple especially under replant conditions. the survey was performed in soil samples coming from apple growing aeras of Germany, Austria and Italy.

Activities performed in the first part of BIO-INCROP project concern five of the eight main objectives fixed in the project proposal. They are:  Evaluation of soil borne pest and pathogens involved in replant disease  Role of rhizospheric bacterial and fungal communities in plant health  Selection of naturally available resources to increase microbial diversity and biomass  Compost and organic amendments  Evaluation of biologically active formulates The document reports main research results and shows main items of dissemination activity performed in the first part of the project.

Apple replant disorders are one of the causes of the downward trend of land planted with apple orchards in Central Europe. A specific transnational survey was thus conducted on apple root associated microorganisms, aimed at increasing the knowledge regarding crop management to counteract this tendency. Soil health was evaluated using a bioassay test with root cuttings of the clonal M9 rootstock, one of the most commonly used rootstocks in Europe. Plant growth response in replant, fallow and gamma ray-sterilized soil was evaluated using soil samples taken from nine orchards selected (three per country) from specialized apple growing areas of Germany, Austria and Italy. Plant growth significantly differed between treatments but not between countries. Root endophytic fungi were confirmed as one of the main components of growth reduction, while endophytic nematodes (Pratylenchus sp.) were not. The large set of quantitative and qualitative data of root endophytic fungi allowed to clarify that Cylindrocarpon-like fungi (Ilyonectria spp. and Thelonectria sp.) had a major pathogenic role in the three countries, while Pythium spp. prevailed as pathogen only in German orchards. Gamma ray-sterilized soil resulted in a more-than-proportional increase of plant growth (42% and 31% respectively vs. replant and fallow) as compared to that observed between fallow and replant soil (18%). This best performance in gamma ray-sterilized soil, in addition to the lowest root colonization by Cylindrocarpon-like fungi in this treatment, appeared to be due to the different composition of fungal communities as compared to two other treatments (fallow and replant soil), which instead were highly similar to each other. This difference was due to a shift of community composition toward Fusarium and binucleate Rhizoctonia, which prevailed in sterilized soil.

The low input means for controlling replant disease under evaluation at DLR Rheinpfalz (Competenzzentrum Gartenbau Rheinbach) are presented.

Introduction The vast majority of apple production in Europe takes place in intensive orchards, this implies the need for intensive capital investment for support structures which then have to be used for a number of generations of trees. Consequently new orchards have to be replanted in the same place as previous plots. This causes soil sickness or yield decline of which “replant disease” is the main biological component. Resulting yield losses are difficult to assess; a recent study in South Tyrol, where 12% of total EU apple is produced, showed that growth reduction can vary from 20 to 60% in replanted orchard compared to fallow control. Severity of this etiology is mediated by plant vigour, physiological state of plants and abiotic factors. Therefore, its occurrence is actually an indicator for fruit growers of the degraded status of biological soil processes. The only effective strategy to control replant disease and crop decline in organic fruit tree orchards is to increase soil diversity, and consequently, the various microbial processes involved in controlling soil borne pathogens, enhancing root growth and mediating plant nutrition. Methods BIO-INCROP, an European transnational project on organic farming, aims to increase knowledge about agro-management practices based on the study of microbial factors involved in soil suppressiveness and biological soil fertility. Project activities are planned on two reference crops: apple and citrus, which represent two main European agro-environments: apple growing areas of Central Europe (Switzerland, Germany, South Tyrol in Italy and Styria in Austria) and Mediterranean citrus growing areas (Valencia region in Spain and the East Mediterranean region of Turkey). Research Actions of the project focus on exploitation of two main categories of natural resources in order to develop innovative cropping practices which will enable soil biodiversity preservation and exploit its biological features. They are: 1. Biological res

Bloei, vruchtzetting, vruchtkleur, oogstdatum en houdbaarheid van de appelcultivar Braeburn in Ahrweiler

Bemestingsadvies op basis van bladanalyse bij Cox, Elstar en Berlepsch