A prototyping method for the re-design of intensive perennial systems: the case of vineyards in France

The results of our re-design and experimentation of grapevine agrosystem, as well as on the other crops (Lançon et al., 2007 and Wery & Langeveld, 2010) show promising perspectives of the prototyping method to achieve high goals for performance and innovation. The complexity of the grapevine agrosystem (ie the number of technical interventions and their potential interactions) requires a strong systemic approach at the interface between the technical and biophysical dimensions of cropping systems (Rapidel et al., 2009). The approach must implement agro-ecological processes to greatly limit inputs. It also required a high innovation and significant changes in the grapevine agrosystem genetics, structure and management. Our results point out the need to re-design grapevine systems from the crop plantation with new varieties, new training systems and with intercrops aiming to improve ecosystem services and maintain a very high level of sustainability criteria

CO-FREE Alternative Test Products for Copper Reduction in Agriculture

The project CO-FREE (2012-2016) aimed to develop strategies to replace/reduce copper use in organic, integrated and conventional farming. CO-FREE alternative test products (CTPs) were tested and integrated together with decision support systems, disease-tolerant varieties, and innovative breeding goals (ideotypes) into improved management strategies. CO-FREE focused on apple/apple scab (Venturia inaequalis), grape/downy mildew (Plasmopara viticola), and tomato and potato/late blight (Phytophthora infestans). Starting point of the project were ten CTPs with direct or indirect modes of action including Trichoderma atroviride SC1 and protein extract SCNB, Lysobacter spp., yeast-based derivatives, Cladosporium cladosporioides H39, the oligosaccharidic complex COS-OGA, Aneurinibacillus migulanus and Xenorhabdus bovienii, sage (Salvia officinalis) extract, liquorice (Glycyrrhiza glabra) extract, PLEX- and seaweed plant extracts. As the project progressed, further promising CTPs were included by the partners. Field trials were performed in different European countries in 2012-2015 following EPPO standards. In the first years, stand-alone applications of CTPs were tested. In the following years these were integrated into complete strategies. Effects on main and further diseases, on yield and on non-target organisms were assessed. Here, field trial results with CTPs are summarized

Nouveaux scénarios pour une transition agroécologique en viticulture

International audienceIn the light of its negative impacts on the environment and human health,conventional agriculture is currently facing new challenges; for example, reducing pesticide reliance, improving biodiversity, adapting to climate change and reconciling winegrowers with consumers, which require changes to be made to vineyard management. A shift towards more sustainable agriculture via the development of agroecological systems may be key to meeting these environmental, economic and social challenges. This study aimed to evaluate the performance of existing viticultural systems, as well as that of three new scenarios that we built to change conventional vine production systems and their related practices. The end aim is to adopt the principles of agroecology and more virtuously, to ensure that vine production remains in line with societal expectations. First, thirty-eight different viticultural systems were chosen. Three realistic scenarios for changing these production systems were then built by working with stakeholders and incorporating the best practices that had been identified in the vineyard. Conventional practices were optimised in the first scenario and an agroecological approach was adopted for the other two scenarios: an Agroecological scenario (using synthetic chemicals) and an Agroecological-Bio scenario (organic system). All three scenarios were based on a combination of good practices which contribute to enhancing vineyard biodiversity, and which thus restore biological regulation and in turn reduce pesticides. The viticultural systems performances have been evaluated with a methodology involving multicriteria decision aid usingELECTRE Tri-C and ELECTRE III methods. Seven evaluation criteria were selected which covered socio-economic performance (economic profitability workload and system complexity) and environmental performance (pesticide pressure, pesticide ecotoxicity, agroecological practices and pesticide drift).The best performances were achieved by the two agroecological scenarios, and this methodology can be adaptable to different production systems everywhere in different viticultural regions.

Foliar fungal communities strongly differ between habitat patches in a landscape mosaic

ABSTRACT Background: Dispersal events between habitat patches in a landscape mosaic can structure ecological communities and influence the functioning of agrosystems. Here we investigated whether short-distance dispersal events between vineyard and forest patches shape foliar fungal communities. We hypothesized that these communities homogenize between habitats over the course of the growing season, particularly along habitat edges, because of aerial dispersal of spores. Methods: We monitored the richness and composition of foliar and airborne fungal communities over the season, along transects perpendicular to edges between vineyard and forest patches, using Illumina sequencing of the Internal Transcribed Spacer 2 (ITS2) region. Results: In contrast to our expectation, foliar fungal communities in vineyards and forest patches increasingly differentiate over the growing season, even along habitat edges. Moreover, the richness of foliar fungal communities in grapevine drastically decreased over the growing season, in contrast to that of forest trees. The composition of airborne communities did not differ between habitats. The composition of oak foliar fungal communities change between forest edge and centre. Discussion: These results suggest that dispersal events between habitat patches are not major drivers of foliar fungal communities at the landscape scale. Selective pressures exerted in each habitat by the host plant, the microclimate and the agricultural practices play a greater role, and might account for the differentiation of foliar fugal communities between habitats

Quantitative traits of pathogenicity of Plasmopara viticola

Quantitative traits of pathogenicity of Plasmopara viticola when inoculated on two different hosts (susceptible: Vitis vinifera cv. Cabernet sauvignon, CS and partially resistant: Cabernet carbon, CC). 108 isolates from the Bordeaux wine region were used and 8 (on CS) and 6 (on CC) leaf discs were inoculated for each isolate (i.e. repetition). The final sample analysed consisted of 1357 leaf discs corresponding to 214 plant-pathogen interactions. Details for each isolate (geographic locations and genetic data) are described in the « PV_genetic_data » file of this package. Cells left blank indicate missing data. The « Latency_Ndays » column indicates the latency period (number of days between inoculation and the first recorded sporangia). The « Sporangium_prod_per_mm2 » column indicates the number of sporangia per mm2 of leaf disc counted at seven days post inoculation (cumulative, over seven days of infection). The « Sporangium_size_µm » column indicates the weighted average of sporangium size. The « nbzoo_per_sporangium » column indicates the number of zoospores contained by each sporangium (on two leaf discs per isolate). The « T50 » column indicates the time at which the pathogen reached 50% of its maximal sporulation at 7 dpi. The « slope_at_T50 » column indicates the slope of the curve (sporulation vs. time) at T50. The « phenotype_CAA » column indicates whether the isolate is resistant or sensitive to CAA fungicides (see the « PV_genetic_data » file of this package). The « phenotype_QOI » column indicates whether the isolate is resistant or sensitive to QoI fungicides (see the « PV_genetic_data » file of this package). The « Fungicide category » column indicates whether the isolate is resistant and/or sensitive to CAA and QoI fungicides

Europe as a bridgehead in the worldwide invasion history of grapevine downy mildew, Plasmopara viticola

International audienceEurope is the historical cradle of viticulture, but grapevines (Vitis vinifera) have been increasingly threatened by pathogens of American origin. The invasive oomycete Plasmopara viticola causes downy mildew, one of the most devastating grapevine diseases worldwide. Despite major economic consequences, its invasion history remains poorly understood. We analyzed a comprehensive dataset of ∼2,000 samples, collected from the most important wine-producing countries, using nuclear and mitochondrial gene sequences and microsatellite markers. Population genetic analyses revealed very low genetic diversity in invasive downy mildew populations worldwide and little evidence of admixture. All the invasive populations originated from only one of the five native North American lineages, the one parasitizing wild summer grape (V. aestivalis). An approximate Bayesian computation-random forest approach allowed inferring the worldwide invasion scenario of P. viticola. After an initial introduction into Europe, invasive European populations served as a secondary source of introduction into vineyards worldwide, including China, South Africa, and twice independently, Australia. Only the invasion of Argentina probably represents a tertiary introduction, from Australia. Our findings provide a striking example of a global pathogen invasion resulting from secondary dispersal of a successful invasive population. Our study will also help designing quarantine regulations and efficient breeding for resistance against grapevine downy mildew

Data from: Soft selective sweeps in fungicide resistance evolution: recurrent mutations without fitness costs in grapevine downy mildew

Adaptation produces hard or soft selective sweeps depending on the supply of adaptive genetic polymorphism. The evolution of pesticide resistance in parasites is a striking example of rapid adaptation that can shed light on selection processes. Plasmopara viticola, which causes grapevine downy mildew, forms large populations, in which resistance has rapidly evolved due to excessive fungicide use. We investigated the pathways by which fungicide resistance has evolved in this plant pathogen, to determine whether hard or soft selective sweeps were involved. An analysis of nucleotide polymorphism in 108 field isolates from the Bordeaux region revealed recurrent mutations of cytb and CesA3 conferring resistance to quinone outside inhibiting (QoI) and carboxylic acid amide (CAA) fungicides, respectively. Higher levels of genetic differentiation were observed for nucleotide positions involved in resistance than for neutral microsatellites, consistent with local adaptation of the pathogen to fungicide treatments. No hitchhiking was found between selected sites and neighbouring polymorphisms in cytb and CesA3, confirming multiple origins of resistance alleles. We assessed resistance costs, by evaluating the fitness of the 108 isolates through measurements of multiple quantitative pathogenicity traits under controlled conditions. No significant differences were found between sensitive and resistant isolates, suggesting that fitness costs may be absent or negligible. Our results indicate that the rapid evolution of fungicide resistance in P. viticola has involved a soft sweep

Data from: Adaptation of a plant pathogen to partial host resistance: selection for greater aggressiveness in grapevine downy mildew

An understanding of the evolution of pathogen quantitative traits in response to host selective pressures is essential for the development of durable management strategies for resistant crops. However, we still lack experimental data on the effects of partial host resistance on multiple phenotypic traits (aggressiveness) and evolutionary strategies in pathogens. We performed a cross-inoculation experiment with four grapevine hosts and 103 isolates of grapevine downy mildew (Plasmopara viticola) sampled from susceptible and partially resistant grapevine varieties. We analysed the neutral and adaptive genetic differentiation of five quantitative traits relating to pathogen transmission. Isolates from resistant hosts were more aggressive than isolates from susceptible hosts, as they had a shorter latency period and higher levels of spore production. This pattern of adaptation contrasted with the lack of neutral genetic differentiation, providing evidence for directional selection. No specificity for a particular host variety was detected. Adapted isolates had traits that were advantageous on all resistant varieties. There was no fitness cost associated with this genetic adaptation, but several trade-offs between pathogen traits were observed. These results should improve the accuracy of prediction of fitness trajectories for this biotrophic pathogen, an essential element for the modelling of durable deployment strategies for resistant varieties

DNA sequences (cytb gene)

DNA sequences (cytb gene