Littérature scientifique sur le sujet « Sustainable viticulture, Fungal diseases, Grapevine protection »

Grapevine trunk diseases (GTDs) threaten the economic sustainability of viticulture, causing reductions of yield and quality of grapes. Biological control is a promising sustainable alternative to cultural and chemical methods to mitigate the effects of pathogens causing GTDs, including Botryosphaeria dieback, Eutypa dieback and Esca. This study aimed to identify naturally occurring potential biological control agents from grapevine sap, cane and pith tissues, and evaluate their in vitro antagonistic activity against selected fungal GTD pathogens. Bacterial and fungal isolates were preliminarily screened in dual culture assays to determine their antifungal activity against Neofusicoccum parvum and Eutypa lata. Among the fungal isolates, Trichoderma spp. inhibited mycelium growth of E. lata by up to 64% and of N. parvum by up to 73%, with overgrowth and growth cessation being the likely antagonistic mechanisms. Among the bacterial isolates, Bacillus spp. inhibited mycelium growth of E. lata by up to 20% and of N. parvum by up to 40%. Selected antagonistic isolates of Trichoderma, Bacillus and Aureobasidium spp. were subjected to further dual culture antifungal analyses against Diplodia seriata and Diaporthe ampelina, with Trichoderma isolates consistently causing the greatest inhibition. Volatile organic compound antifungal analyses showed that these Trichoderma isolates inhibited mycelium growth of N. parvum (20% inhibition), E. lata (61% inhibition) and Dia. ampelina (71% inhibition). Multilocus sequence analyses revealed that the Trichoderma isolates were most closely related to Trichoderma asperellum and Trichoderma hamatum. This study had identified grapevine sap as a novel source of potential biological control agents for control of GTDs. Further testing will be necessary to fully characterize modes of antagonism of these microorganisms, and assess their efficacy for pruning wound protection in planta.

The viticulture and wine industry contribute to the economy and reputation of many countries all over the world. With the predicted climate change, a negative impact on grapevine physiology, growth, production, and quality of berries is expected. On the other hand, the impact of these changes in phytopathogenic fungi development, survival rates, and host susceptibility is unpredictable. Grapevine fungal diseases control has been a great challenge to winegrowers worldwide. The use of chemicals in viticulture is high, which can result in the development of pathogen resistance, increasingly raising concerns regarding residues in wine and effects on human and environmental health. Promoting sustainable patterns of production is one of the overarching objectives and essential requirements for sustainable development. Alternative holistic approaches, such as those making use of biostimulants, are emerging in order to reduce the consequences of biotic and abiotic stresses in the grapevine, namely preventing grape fungal diseases, improving grapevine resistance to water stress, and increasing yield and berry quality.

Grapevine trunk diseases (GTD) are currently one of the most devastating and challenging diseases in viticulture, leading to considerable yield losses and a remarkable decline in grapevine quality. The identification of the causal agents is the cornerstone of an efficient approach to fighting against fungal diseases in a sustainable, non-chemical manner. This review attempts to describe and expose the symptoms of each pathology related to GTD, the modes of transmission, and the harmfulness of recently reported agents. Special attention was given to new diagnostic tests and technologies, grapevine defense mechanisms, molecular mechanisms of endophytes fungal colonization, and management strategies used to control these threats. The present extended review is, therefore, an updated state-of-the-art report on the progress in the management of vineyards.

Replacing Bordeaux broth and synthetic fungicides by less invasive approaches of fungal disease control remains a challenge for both conventional and organic viticulture. Silicon (Si) application has been proposed as a viable alternative for the control of pathogens and other stresses in agriculture. In a three-year field trial, we tested the effect of foliar and soil application of colloidal silicon on its availability in vineyard soil and pants, the performance and quality of yield, and finally, the control of powdery mildew for grapevine cv. Grüner Veltliner. Soil application of colloidal silicon increased plant-available Si, but only foliar application increased the total silicon concentrations in leaves, yield, and cluster weight. Moreover, the wine produced from the silica-treated grapes were ranked better in sensory evaluations. Our findings provide evidence for the potential of at least partially replacing conventional fungicides, rendering viticulture more sustainable in terms of soil protection and biodiversity. Silicon applications are low in costs and comply with the principles of organic wine production.

Grapevine trunk diseases (GTDs) are currently considered some of the most important challenges for viticulture, curtailing vineyard longevity and productivity in nearly every raisin, table and wine grape production region in California and worldwide. Pruning wounds provide the main entry point for fungal pathogens responsible for these diseases; pathogens enter the wounds following precipitation events. The aim of this study was to evaluate the efficacy of selected chemical and experimental biological fungicides for protection of pruning wounds against two of the most common and virulent fungal pathogens causing GTDs: Eutypa lata and Neofusicoccum parvum. This study was conducted on sauvignon blanc at the UC Davis Department of Plant Pathology Field Station. Results showed that several chemical and biological fungicides, notably the chemical fungicide Luna Sensation, the biofungicide Vintec and a combination of the biofungicides Bio-Tam and CrabLife Powder, provided significant protection against at least one of the two canker pathogens used in this study. However, the majority of products tested did not provide simultaneous control of both E. lata and N. parvum pathogens, highlighting the continuing challenge of controlling GTDs.

Switzerland is a pioneer country in the development of integrated production (IP) and integrated pest management (IPM). The overall goal is sustainability at the ecological, economic and social level to produce high quality grapes. In 1993, the IP-IPM head-organisation VITISWISS was created. The starting points were the improvement of pest management by the biocontrol of spider mites and the control of grape berry moths by mating disruption and an optimal soil management, followed over the years by state-of-the-art sprayer calibration, development of disease forecasting models (AgroMeteo, VitiMeteo), leaf-area adapted dosage of plant protection products, enhanced biodiversity, water and cover crop management. The efforts and the results gained in a continuous education process by the growers are considerable, but not enough for consumers and politics concerned by the use of plant protection products. The absence of acaricides and insecticides as well as forecasting systems available on the internet (www.agrometeo.ch) for the control of downy and powdery mildew, represent the major progresses. Where mechanisation is possible, herbicides can progressively be replaced by mechanical technics, which is not possible in steep vineyards. The general irrational unscientific trend against “synthetic” plant protection products requests alternatives for the control of fungal diseases and for cover crop management under the vine rows to avoid excessive water-nitrogen competition particularly in the actual context of climate change.

Rootstocks are the link between the soil and scion in grapevines, can provide tolerance to abiotic and biotic stresses, and regulate yield and grape quality. The vascular system of grapevine rootstocks in nurseries is still an underexplored niche for research, despite its potential for hosting beneficial and pathogenic microorganisms. The purpose of this study was to investigate the changes in the composition of fungal communities in 110 Richter and 41 Berlandieri rootstocks at four stages of the grapevine propagation process. Taxonomic analysis revealed that the fungal community predominantly consisted of phylum Ascomycota in all stages of the propagation process. The alpha-diversity of fungal communities differed among sampling times for both rootstocks, with richness and fungal diversity in the vascular system decreasing through the propagation process. The core microbiome was composed of the genera Cadophora, Cladosporium, Penicillium and Alternaria in both rootstocks, while the pathogenic genus Neofusicoccum was identified as a persistent taxon throughout the propagation process. FUNguild analysis showed that the relative abundance of plant pathogens associated with trunk diseases increased towards the last stage in nurseries. Fungal communities in the vascular system of grapevine rootstocks differed between the different stages of the propagation process in nurseries. Numerous genera associated with potential biocontrol activity and grapevine trunk diseases were identified. Understanding the large diversity of fungi in the rootstock vascular tissue and the interactions between fungal microbiota and grapevine will help to develop sustainable strategies for grapevine protection.

Downy and powdery mildews are major grapevine diseases. In organic viticulture, a few fungicides with protectant activities (copper and sulphur in particular) can be used, and their preventative application frequently leads to unneeded spraying. The adoption of an epidemiological disease forecasting model could optimise the timing of treatments and achieve a good level of disease protection. In this study, the effectiveness of the EPI (Etat Potentiel d’Infection) model in predicting infection risk for downy and powdery mildews was evaluated in nine organic vineyards located in Panzano in Chianti (FI), over a 2-year period (2020–2021). The reliability of the EPI model was investigated by comparing the disease intensities, the number of fungicide sprayings, the quantities of the fungicides (kg/ha), and the costs of the treatment achieved, with or without the use of the model, in a vineyard. The results obtained over two seasons indicated that, in most cases, the use of the EPI model accurately signalled the infection risk and allowed for a reduction in the frequency and cost of spraying, particularly for powdery mildew control (−40% sprayings, −20% costs compared to the farmer’s schedule), without compromising crop protection. The use of the EPI model can, therefore, contribute to more-sustainable disease management in organic viticulture.

In most wine-growing countries of the world the interest for organic viticulture and eco-friendly grape production processes increased significantly in the last decade. Organic viticulture is currently dependent on the availability of Cu and S compounds, but their massive use over time has led to negative effects on environment health. Consequently, the purpose of this study was to evaluate the effectiveness of alternative and sustainable treatments against powdery mildew, gray mold and sour rot under the field conditions on Nero d’Avola and Inzolia Sicilian cultivars. In detail, the efficacy of COS-OGA, composed by a complex of oligochitosans and oligopectates, and its effects in combination with arbuscular mycorrhizal fungi (AMF) were evaluated to reduce airborne disease infections of grape. COS-OGA combined with AMF induced a significant reduction in powdery mildew severity both on Nero d’Avola and Inzolia with a mean percentage decrease of about 15% and 33%, respectively. Moreover, COS-OGA alone and combined with AMF gave a good protection against gray mold and sour rot with results similar to the Cu–S complex (performance in disease reduction ranging from 65 to 100%) on tested cultivars. Similarly, the COS-OGA and AMF integration provided good performances in enhancing average yield and did not negatively impact quality and microbial communities of wine grape. Overall, COS-OGA alone and in combination could be proposed as a valid and safer option for the sustainable management of the main grapevine pathogens in organic agroecosystems.

Grapevine trunk diseases (GTDs) are caused by multiple unrelated fungal pathogens, and their management remains difficult worldwide. Biocontrol is an attractive and sustainable strategy given the current need for a cleaner viticulture. In this study, twenty commercial vineyards were sampled across California to isolate endophytic and rhizospheric bacteria from different grapevine cultivars with the presence and absence of GTD symptoms. A collection of 1344 bacterial isolates were challenged in vitro against Neofusicoccum parvum and Diplodia seriata, from which a subset of 172 isolates exerted inhibition levels of mycelial growth over 40%. Bacterial isolates were identified as Bacillus velezensis (n = 154), Pseudomonas spp. (n = 12), Serratia plymuthica (n = 2) and others that were later excluded (n = 4). Representative isolates of B. velezensis, P. chlororaphis, and S. plymuthica were challenged against six other fungal pathogens responsible for GTDs. Mycelial inhibition levels were consistent across bacterial species, being slightly higher against slow-growing fungi than against Botryosphaeriaceae. Moreover, agar-diffusible metabolites of B. velezensis strongly inhibited the growth of N. parvum and Eutypa lata, at 1, 15, and 30% v/v. The agar-diffusible metabolites of P. chlororaphis and S. plymuthica, however, caused lower inhibition levels against both pathogens, but their volatile organic compounds showed antifungal activity against both pathogens. These results suggest that B. velezensis, P. chlororaphis and S. plymuthica constitute potential biocontrol agents (BCAs) against GTDs and their application in field conditions should be further evaluated.

Ce travail a consisté en l'étude l'application du phosphate de calcium comme système de transporteur (" drug delivery ") pour la protection de la vigne (Vitis vinifera L.). Ce biomatériau a été étudié avec succès dans le domaine médical, de la fonctionnalité du phosphate de calcium avec des molécules anticancéreuses, à la mise au point d'un dentifrice innovant. Des essais préliminaires dans le contrôle des maladies fongiques de la vigne ont révélé des résultats prometteurs.Dans ce contexte, l'hydroxyapatite inorganique et biomimétique a été étudié en tant que système transporteur potentiel de substances bioactives autorisées en agriculture biologique pour la protection des plantes. À travers une approche multidisciplinaire, l'objectif de l'étude était d'évaluer l'efficacité de l'hydroxyapatite dans l'amélioration de l'activité biologique des composés de cuivre(II) pour lutter contre des maladies fongiques telles que le mildiou et les maladies du bois. Cette étude a pour ambition de contribuer à l'optimisation de la distribution et de la persistance des substances bioactives dans les tissus végétaux, y compris vasculaires, où des pathogènes nocifs peuvent se développer ainsi qu'à la réduction des quantités de fongicides.Cette recherche a ainsi permis de (i) comprendre l'interaction entre le système transporteur, la substance fonctionnelle et les tissus de la vigne ; (ii) démontrer le mécanisme sur lequel l'efficacité supérieure de la substance fonctionnelle est basé ; (iii) recueillir de nouvelles informations sur les mécanismes impliqués dans l'expression des symptômes des maladies du bois en étudiant les réactions de défense des plantes induites par les traitements
The research investigates the application of biomimetic calcium phosphate as innovative delivery system for grapevine (Vitis vinifera L.) protection purposes. This smart material was successfully studied in the biomedical field, from the functionalization of biomimetic calcium phosphate with anti-cancer molecules for localized releases, to the development of an innovative toothpaste for oral hygiene. Preliminary assays to implement the control of the grapevine fungal diseases, have revealed promising results. In this framework, the biomimetic inorganic hydroxyapatite was investigated as potential delivery system of bioactive substances allowed in organic agriculture for plant protection.Through a multidisciplinary approach, the study was aimed to evaluate the efficiency of hydroxyapatite in enhancing the biological activity of copper(II) compounds, on the control of relevant common diseases, like downy mildew, and complex fungal diseases, such as the grapevine trunk diseases. This aim is related to further ambitious goals: the significant reduction of the fungicides amounts applied in plant protection and the optimization of the distribution and persistence of the bioactive substances in the plant tissues, including the vascular ones, where harmful pathogens can develop. Overall, the experimental activities allowed: (i) to understand the interaction between delivery system, functional substance and grapevine tissues; (ii) to demonstrate the mechanism on which the higher efficacy of the functional substance is based; (iii) to collect new information on the mechanisms involved in the symptoms expression by studying the plant defense reactions induced by the treatments

Grapevine productions is worldwide affected by fungal pathogens both in the field and during post-harvest storage. In addition to yield losses, even the quality of grape and wine is affected. The management of these pathogens mainly relies on chemicals and agronomical practices. The majority of the plant protection products (PPPs) distributed in the vineyard are directed to control Botrytis cinerea and Plasmopara viticola, causal agents of gray mold and downy mildew disease, respectively. However, pathogens can develop resistance to synthetic fungicides. Moreover, the high use of PPPs poses serious risks to the environment and the health of operators and consumers. In this regard, European Union (UE) policies foresee a 50% reduction in the use of chemical pesticides by 2030 and the implementation of integrated approaches for crop protection. The research studies presented in this thesis share the final purpose to find out new alternative strategies and molecules to counteract grapevine pathogens. To this aim, a deep knowledge of the pathogenic mechanism is fundamental. Therefore, in the first part of the thesis the interaction between B. cinerea and grapevine was investigated by characterizing the ability of this fungus to detoxify plant defense proteins. During ripening, grape berries accumulate a class IV chitinase, a pathogenesis related (PR) protein with antifungal activity. However, the protease activity of B. cinerea is able to cleave this chitinase impairing its antifungal activity. This research could represent a first step into the identification of new fungal virulence factors to be counteracted. The second part of the thesis focused on the development of new biopesticides active against P. viticola and B. cinerea. The effectiveness of several water-soluble analogs produced by targeted amino acid substitutions of an antimicrobial peptide (peptaibol) naturally produced by Trichoderma longibrachiatum, was evaluated against the two pathogens. The assays allowed to identify a peptide highly effective against both pathogens that may be developed as biopesticide.
Grapevine productions is worldwide affected by fungal pathogens both in the field and during post-harvest storage. In addition to yield losses, even the quality of grape and wine is affected. The management of these pathogens mainly relies on chemicals and agronomical practices. The majority of the plant protection products (PPPs) distributed in the vineyard are directed to control Botrytis cinerea and Plasmopara viticola, causal agents of gray mold and downy mildew disease, respectively. However, pathogens can develop resistance to synthetic fungicides. Moreover, the high use of PPPs poses serious risks to the environment and the health of operators and consumers. In this regard, European Union (UE) policies foresee a 50% reduction in the use of chemical pesticides by 2030 and the implementation of integrated approaches for crop protection. The research studies presented in this thesis share the final purpose to find out new alternative strategies and molecules to counteract grapevine pathogens. To this aim, a deep knowledge of the pathogenic mechanism is fundamental. Therefore, in the first part of the thesis the interaction between B. cinerea and grapevine was investigated by characterizing the ability of this fungus to detoxify plant defense proteins. During ripening, grape berries accumulate a class IV chitinase, a pathogenesis related (PR) protein with antifungal activity. However, the protease activity of B. cinerea is able to cleave this chitinase impairing its antifungal activity. This research could represent a first step into the identification of new fungal virulence factors to be counteracted. The second part of the thesis focused on the development of new biopesticides active against P. viticola and B. cinerea. The effectiveness of several water-soluble analogs produced by targeted amino acid substitutions of an antimicrobial peptide (peptaibol) naturally produced by Trichoderma longibrachiatum, was evaluated against the two pathogens. The assays allowed to identify a peptide highly effective against both pathogens that may be developed as biopesticide.

The research investigates the application of biomimetic calcium phosphate as innovative delivery system for grapevine (Vitis vinifera L.) protection purposes. This smart material was successfully studied in the biomedical field, from the functionalization of biomimetic calcium phosphate with anti-cancer molecules for localized releases, to the development of an innovative toothpaste for oral hygiene. Preliminary assays to implement the control of the grapevine fungal diseases, have revealed promising results. In this framework, the biomimetic inorganic hydroxyapatite was investigated as potential delivery system of bioactive substances allowed in organic agriculture for plant protection. Through a multidisciplinary approach, the study was aimed to evaluate the efficiency of hydroxyapatite in enhancing the biological activity of copper(II) compounds, on the control of relevant common diseases, like downy mildew, and complex fungal diseases, such as the grapevine trunk diseases. This aim is related to further ambitious goals: the significant reduction of the fungicides amounts applied in plant protection and the optimization of the distribution and persistence of the bioactive substances in the plant tissues, including the vascular ones, where harmful pathogens can develop. Overall, the experimental activities allowed: (i) to understand the interaction between delivery system, functional substance and grapevine tissues; (ii) to demonstrate the mechanism on which the higher efficacy of the functional substance is based; (iii) to collect new information on the mechanisms involved in the symptoms expression by studying the plant defense reactions induced by the treatments.