French Vineyards Research Articles

Knowledge description for the suitability requirements of different geographical regions for growing wine

The production of wine has progressed on every main continent. The knowledge modeling can support the sharing of expertise, methods and good practice concerning international grape vine growing and wine production while maintaining a high level of quality. Our research focuses specifically on the development of a support system for knowledge formalization. We describe some procedural rules to represent experienced knowledge in the viticulture domain and plant pathology. We use a graphical software for rules management. The visual representation is a step toward the improvements of interaction between Artificial Intelligence methods and domain experts to make interpretable learning models for concrete decisions. This implementation enables us to make valuable visual reasoning to search whether the Chinese regions are capable of receiving a production of French vineyards. In particular, one outcome is that two Chinese regions appear more favorable and consistent for the development of wine from the Bordeaux region.

The competitiveness of French protected designation of origin wines: a theoretical analysis of the role of proximity

The French model based upon the protected designation of origin (PDO) has been challenged since the beginning of the last decade by the one of ‘New World Wines'. Yet, not all PDO vineyards are equally affected, while some new world wines have in turn entered into crisis. We will consider the issue by comparing two French vineyards, Cahors and Chablis, according to the ‘economics of proximity' framework. We will first analyse the dynamics and strategies of the French wine industry according to the above-mentioned framework, detailing more precisely the terroir-based strategy. We will then apply it to our two case studies, in order to understand the challenges currently facing the French wine industry.

French vineyards provide information that opens ways for effective resistance management of Botrytis cinerea (grey mould)

Resistance to fungicides is an evolutionary process resulting from the selection of advantageous genotypes in naturally diverse populations. Seven fungicide modes of action are authorised to control grey mould caused by Botrytis cinerea on grapevine in France, and five of them have encountered specific resistance, with variable frequencies in populations and possible consequences for field fungicide efficacy. Moreover, multidrug resistance is caused by fungicide efflux and allows a weak resistance towards six unrelated modes of action. Here, a review is given of the fungicide resistance status of B. cinerea in France, particularly in the vineyards of Champagne, which are the most affected. Recently developed resistance and recent findings concerning the associated resistance mechanisms are focused upon in particular. Finally, antiresistance strategies are presented, and examples of managed resistance are discussed in a more general manner with the aim of extending this knowledge to other crops and countries undergoing similar resistance problems.

Pesticides in roof runoff: Study of a rural site and a suburban site

The quality of stored roof runoff in terms of pesticide pollution was assessed over a one-year period. Two tanks, located at a rural and suburban site, respectively, were sampled monthly. The two studied collection surface were respectively a tile slope roof and a bituminous flat roof. Four hundred and five compounds and metabolites were screened using liquid and gas chromatography coupled with various detection systems. Principal Component Analysis was applied to the data sets to elucidate patterns. At the rural site, two groups of compounds associated with two different types of agriculture, vineyard and crops, were distinguished. The most frequently detected compound was glyphosate (83%) which is the most commonly used herbicide in French vineyards. At the suburban site, quantified compounds were linked to agriculture rather than urban practices. In addition, all samples were contaminated with mecoprop which is a roof-protecting agent. Its presence was attributed to the nature of roofing material used for rainwater collection. For both sites, the highest number and concentrations of compounds and metabolites were recorded at the end of spring and through summer. These results are consistent with treatment periods and higher temperatures.

Role of sterol 3‐ketoreductase sensitivity in susceptibility to the fungicide fenhexamid in Botrytis cinerea and other phytopathogenic fungi

The narrow-spectrum fungicide fenhexamid was introduced into French vineyards in 2000 to control grey mould caused by a complex of two cryptic species: Botrytis cinerea, the predominant species sensitive to fenhexamid, and Botrytis pseudocinerea, naturally resistant. Fenhexamid was suggested to inhibit the 3-ketoreductase involved at C-4 demethylation steps during ergosterol biosynthesis, as revealed by its effects on the B. cinerea sterol profile. Resistance monitoring studies have hitherto identified two B. cinerea fenhexamid-resistant phenotypes, both resulting from mutations in the erg27 gene encoding 3-ketoreductase. The role of 3-ketoreductase sensitivity in fungal susceptibility to fenhexamid was investigated by studying sterol profiles and microsomal 3-ketoreductase in various fungal strains. Fenhexamid does inhibit B. cinerea 3-ketoreductase activity. Erg27 mutations causing amino acid substitutions in or near the transmembrane domain strongly decrease the affinity of fenhexamid for 3-ketoreductase. Fenhexamid has very low affinities for 3-ketoreductase in inherently resistant species, whether closely related to B. cinerea, like B. pseudocinerea, or more distantly related, like Nectria haematococca. erg27 mutation and erg27 polymorphism may therefore contribute to the unfavourable binding of fenhexamid to its target, 3-ketoreductase, explaining the acquisition of fenhexamid resistance in B. cinerea and the narrow spectrum of this fungicide.

The role of the mealybug Phenacoccus aceris in the spread of Grapevine leafroll-associated virus −1 (GLRaV-1) in two French vineyards

Spread patterns of a Grapevine leafroll-associated virus 1 (GLRaV-1) epidemic and a mealybug infestation survey over 10 year were recorded in two Burgundy French vineyards to investigate the relation between them. The temporal evolution of leafroll spread at both study sites was compared on disease incidence data with logistic regression models. We first tested if the spatial distribution of the disease and the mealybug were aggregated using permutation methods, then we tested the independence between the two spatial patterns by randomly shifting one pattern. In Bonzon, an increase from 5 % to 86 % of leafroll prevalence was observed over an 8-year time span, whereas leafroll prevalence remained stable around 5 % in Marsannay-la-Cote during the same period. In Bonzon, the disease spread rapidly from older neighbouring vineyards in four main patches while no spread of the disease was recorded from infected vines in Marsannay-la-Cote. The mealybug Phenacoccus aceris was recorded on 74 % of vines in Bonzon throughout the study and only 6 % of vines in Marsannay-la-Cote. In the latter location, the disease was not associated with the presence of the mealybug, so that it may have arisen from infected plant material escaping the sanitary inspection. In Bonzon, the significant statistical correlation between the mealybug distribution and diseased plants suggests that P. aceris was responsible for the rapid spread of GLRaV-1 in the vineyard. This is the first report of GLRaV-1 natural spread in Europe.

Electromagnetic induction (EMI) measurements as a proxy of earthworm presence in Southern French vineyards

Electromagnetic induction (EMI) is a non-invasive geophysical technique for studying the physical and chemical features of soil distribution. This paper focuses on the relations of the apparent electrical conductivity (ECa) of soil, measured using a Profiler GSSI EMP-400, with soil abiotic and biotic parameters: volumetric water content, pH, electrical conductivity, coarse elements, density and biomass of different earthworm ecological categories (anecics and endogeics). Trials were carried out in nine commercial vineyards in Languedoc-Roussillon (France) cultivated according to different soil management technologies: grass cover, chemical weeding and tillage. Hand sorting and a mustard method were used to measure the earthworms. Strong relationships between the abundance and biomass of anecic and endogeic earthworms and ECa values were found, particularly in grass covered and chemically weeded plots. This result is supported by the high determination coefficients found (R2 from 0.53 to 0.94). Our results suggest that the EMI signal, as an integrated value of the physical–chemical conditions of soil, represents a real possibility for reducing the number of laborious earthworm samplings, by guaranteeing the reliability of the estimates of mean real values of earthworm parameters and their surface spatial distribution. EMI could therefore be a useful tool to spatialize and to predict the presence of earthworms in fields in perennial crops.

How are nematode communities affected during a conversion from conventional to organic farming in southern French vineyards?

The rate of conversion from conventional vineyards to organic farming practices is increasing. Organic farming improves some soil properties, although some organic practices have negative effects on soils. The objective of this work was to study the long-term effects of organic farming through the use of soil nematodes as bio-indicators of soil processes. Our experimentation was conducted in a commercial vineyard where plots belonged to two types of viticulture: conventional viticulture and organic viticulture (for 7, 11 and 17 years). The nematode community structure and nematode indices were determined. The main result was that organic practices increased soil nematode density. An increase in the available resources, as measured by a higher enrichment index (EI), led to an increase in the microbial feeder density and mainly opportunistic fungal-feeding nematodes. A greater density of plant-feeding nematodes was attributed to the presence of a grass cover. The functioning of the soil was shifted with the decomposition channel of the soil organic matter becoming more fungal than bacterial. Even though changes were observed in the nematode community structure following the conversion, the maturity index (MI), the plant-parasitic index (PPI) and the structure index (SI) remained constant. Consequently, the organic practices did not improve the soil food web length or complexity even though the biological activity, as measured by microbial biomass and total nematode density, increased.

Ecological and physiological effects of soil management practices on earthworm communities in French vineyards

In recent literature, very few studies have reported the use of the combination of indicators from ecological communities and ecotoxicity biomarkers in field experiments to assess agricultural quality. Therefore, the aim of this study was to determine the influence of three soil management practices of vine inter-rows (chemical weeding, mechanical weeding and grass-covering) on earthworms, in the Gaillac vineyard (South-West France). The sampling, identification and counts of earthworms were performed in spring and autumn over three years in order to determine the influence of the management practices. Focussing on the most abundant species, Aporrectodea nocturna, biomarker assays (glutathione-S-transferase (GST), catalase (CAT) and cholinesterase (ChE) activities) were conducted to check physiological disturbances that are indirectly linked to soil management practices.A strong influence of soil management practices was highlighted on earthworm ecology and physiology in the vine inter-rows. Chemical weeding favoured worm proliferation, but proportionally decreased the number of epi-anecic species. Mechanical weeding dramatically decreased the total number of earthworms, both adults and juveniles, and their biomass. Under these soil farming practices, variations of metabolisation and anti-oxidant enzyme activities were observed, suggesting an increase in pesticide bioavailability. Grass-covering seemed to be the best practice, at least from an environmental point of view. Neurotoxicity enzyme (cholinesterase) activity in vineyard earthworms was not affected by pollutants conventionally sprayed on the vineyard, regardless of soil agricultural practice.It was concluded that soil management practices can both modify earthworm communities and physiology, inducing variations of the following factors: protection against predators, environmental conditions and availability of pesticide and nutrients.

Collective Innovation Boosts Biodiversity in French Vineyards

The need to mainstream biodiversity into agricultural activities has been advocated for some time. Several approaches have been described, ranging from plot to farm or landscape scale and involving different practices. We studied the development of a biodiversity enhancing project in French vineyards based on agronomic and sociological data. We conducted interviews and farm surveys to analyze management practices influencing biodiversity both within fields and in adjacent areas not used for production. We studied farmers' motivations to join the winegrowers' association project and their perception of the importance of biodiversity in their own vineyard management. Results show that individual initiative and the farmers' association both played a key role in project development, even though people's perception of biodiversity matters and personal involvement had been extremely variable. Although the project can be considered a collective success, it remains difficult for winegrowers, individually, to take biodiversity into account in their agronomic practices.

CLIMATE CHANGE IMPACT ON FRENCH VINEYARDS AS PREDICTED BY MODELS

ISHS XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on the Effect of Climate Change on Production and Quality of Grapevines and their Products CLIMATE CHANGE IMPACT ON FRENCH VINEYARDS AS PREDICTED BY MODELS

Stealing to Survive: Crime and Income Shocks in 19th Century France

Using local administrative data from 1826 to 1936 we document the evolution of crime rates in 19th century France and we estimate the impact of a negative income shock on crime. Our identification strategy exploits the phylloxera crisis. Between 1863 and 1890, phylloxera destroyed about 40% of French vineyards. Using the geographical variation in the timing of this shock we instrument wine production and we identify the effects of the shock on property and violent crime rates. Our estimates suggest that the phylloxera crisis did not significantly impact violent crimes but caused an increase in property crimes of about 9%.

The use of pesticides in French viticulture: a badly controlled technology transfer!

The use of pesticides is one of the techniques employed in modern agriculture and in particular in intensive agriculture. The risks for the environment and for worker health have been debated in western countries for about ten years. Recent developments in epidemiology, toxicology and ergotoxicology have clearly revealed that pesticides could harm the health of farmers (cancers, neurological diseases and reproductive disorders). Failures and shortcomings in the risk prevention systems have also come to light. This paper aims to address the risks associated to the use of pesticides in French vineyards. The chosen approach draws from an anthropological approach as well as from developments in ergotoxicology applied to the French vineyard work. We shall discuss the use of pesticides from the point of view of the transfer of technology. Our recent research has shown that this technology transfer was not completely controlled by the different stakeholders.

Strong resistance to the fungicide fenhexamid entails a fitness cost in Botrytis cinerea, as shown by comparisons of isogenic strains

Fenhexamid, a sterol biosynthesis inhibitor effective against Botrytis, inhibits the 3-ketoreductase (Erg27) involved in C-4 demethylation. Several fenhexamid-resistant phenotypes have been detected in Botrytis cinerea populations from French vineyards. The field isolates with the highest resistance levels display amino acid changes in Erg27 (F412S, F412I or F412V). Fenhexamid-resistant mutants were generated by site-directed mutagenesis of the erg27 gene in a sensitive recipient strain to overcome the impact of different genetic backgrounds. The wild-type erg27 allele was replaced by the three mutated alleles (erg27(F412S/I/V)) by homologous recombination. These isogenic strains were shown to be fenhexamid-resistant and were used to quantify the impact of F412 mutations on fungal fitness. Several parameters, including radial growth, the production of sclerotia and conidia, freezing resistance and aggressiveness, were quantified in laboratory conditions. Analysis of variance demonstrated significant differences between the mutant and parental strains for some characters. In particular, the mutants grew more slowly than the wild-type strain and displayed variations in the production of sclerotia and conidia with temperature and susceptibility to freezing. The results highlight a moderate but significant impact of F412 mutations on the survival capacity of B. cinerea strains displaying high levels of resistance to fenhexamid in laboratory conditions, potentially limiting their dispersal and persistence, particularly in terms of overwintering, in field conditions.

Nematodes Go Viral

Nematodes Go Viral

Long-Run Health Impacts of Income Shocks: Wine and Phylloxera in Nineteenth-Century France

Between 1863 and 1890, phylloxera destroyed 40% of French vineyards. Using the regional variation in the timing of this shock, we identify and examine the effects on adult height, health, and life expectancy of children born in the years and regions affected by the phylloxera. The shock decreased long-run height, but it did not affect other dimensions of health, including life expectancy. We find that those born in affected regions were about 1.8 millimeters shorter than others at age 20, a significant effect since average heights grew by only 2 centimeters in the entire nineteenth century.

Assessment of fungicide resistance and pathogen diversity in Erysiphe necator using quantitative real‐time PCR assays

Management of grapevine powdery mildew Erysiphe necator Schw. requires fungicide treatments such as sterol demethylation inhibitors (DMIs) or mitochondrial inhibitors (QoIs). Recently, reduction in the efficacy of DMIs or QoIs was reported in Europe and the United States. The aim of the present study was to develop real-time qPCR tools to detect and quantify several CYP51 gene variants of E. necator: (i) A versus B groups (G37A) and (ii) sensitive versus resistant to sterol demethylase inhibitor fungicides (Y136F). The efficacy of the qPCR tools developed was better than the CAPS method, with a limit of 2 pg for E necator DNA, 0.06 ng for genetic group A and 1.4 ng for the DMI-resistant allele. The detection limits of qPCR protocols (LOD) ranged from 0.72 to 0.85%, and the quantification limits (LOQ) ranged from 2.4 to 2.85% for the two alleles G47A and Y136F respectively. The application of qPCR to field isolates from French vineyards showed the presence of DMI-resistant and/or QoI-resistant alleles in French pathogen populations, linked to genetic group B. The real-time PCR assay developed in this study provides a potentially useful tool for efficient quantification of different alleles of interest for fungicide monitoring and for population structure of E. necator.

AFLP markers reveal two genetic groups in the French population of the grapevine fungal pathogen Phaeomoniella chlamydospora

Phaeomoniella chlamydospora, (Chaetothyriales, Herpotrichiellaceae) is one of the main causal agents of Petri disease and esca on grapevines. We have used AFLP markers to study the population genetic structure of 74 isolates collected at different spatial scales: 56 isolates originated from vines with esca disease sampled from four French vineyards (Poitou-Charentes, Aquitaine, Languedoc-Roussillon, Alsace); 18 isolates were collected from a single plot (Aquitaine vineyard). Significant linkage disequilibrium indicated that P. chlamydospora populations are not panmictic, whereas the level of haplotypic diversity observed, 72 single multilocus haplotypes identified in total among the 74 isolates analysed, suggest that reproduction in this species may not be strictly clonal. Clustering analyses suggests the presence of two genetically differentiated but sympatric clusters of isolates. The level of differentiation between the two clusters is high (FST = 0.23) and significant at 13 out of the 21 loci analyzed. The most plausible explanation for this pattern of admixture is the coexistence in P. chlamydospora French populations of two predominant clonal lineages. Finally, the low level of spatial genetic differentiation in this study is consistent with the spread of this fungus through the transport of infected plant material by human activities.

Molecular strategies to enhance the genetic resistance of grapevines to powdery mildew

The Eurasian winegrape Vitis vinifera has little or no genetic resistance to the major fungal pathogens, powdery mildew (Erysiphe necator) and downy mildew (Plasmopora viticola). These pathogens were first introduced into French vineyards from North America in the 1800s before spreading to all major grape producing regions of the world. As a result, grape production is highly dependent on the use of fungicides. With the increasing financial and environmental costs of chemical application and the emergence of fungicide-resistant strains, the introduction of natural genetic resistance against these fungal pathogens is a high priority for viticultural industries worldwide. We are utilising a number of different molecular approaches to increase our understanding of the basis of resistance to these important major fungal pathogens and to identify potential new sources of genetic resistance. This review will outline the progress and the potential of each of these different molecular strategies to the generation of fungal-resistant grapevine germplasm.

Resistance to Plasmopara viticola in grapevine ‘Bianca’ is controlled by a major dominant gene causing localised necrosis at the infection site

Downy mildew resistance is a quantitative trait in grapevines of the genus Vitis. The grapevine 'Bianca' has retained resistance, originally present in its North American ancestors, through several cycles of backcrossing with susceptible cultivars of Vitis vinifera followed by phenotypic selection. The genetic control of the trait was studied using 116 full-siblings from the cross 'Chardonnay' x 'Bianca' and parental genetic maps consisting of 298 and 312 markers, respectively. Ratings of resistance and histological identification of the stage of interaction, when pathogen development is impaired in resistant individuals, were performed using leaf disc inoculation assays with two isolates of Plasmopara viticola collected in Italian and French vineyards. 'Bianca' and 59% of its offspring were heterozygous for a dominant gene, located in a 2.9 cM interval at the Rpv3 locus on chromosome 18, responsible for the onset of a hypersensitive response (HR) at the infection sites within 2 days post inoculation (dpi). Localised necrosis was the earliest phenotypic difference compared to susceptible individuals, it did not halt pathogen growth, but it was associated with a significant reduction of pathogen performance and disease symptoms from 3 to 6 dpi. QTL peaks for quantitative ratings revealed the strongest effects being caused by the Rpv3 locus: extent of mesophyll colonisation (LOD 3.1, percentage of explained phenotypic variance 16.2%), sporulation density (29.7, 74.3%), and symptom severity expressed by the OIV452 descriptor recommended by the Office International de la Vigne et du Vin (28.3, 74.6%). Strong correlation was observed between the ability of a seedling to mount an HR under controlled experimental conditions and quantitative resistance of the adult plant exposed to natural infections in the field, which was expressed by the number of leaves with fungal sporulation, in two consecutive years of observations.