Disease Of Grapevine Research Articles

Droplet Digital PCR: A New Molecular Method to Detect G1105S/V Mutations in Plasmopara viticola CesA3 Gene

Plasmopara viticola is the causal agent of Grapevine Downy Mildew (GDM), which is a devastating disease of grapevines in humid temperate regions. The most employed method for protecting grapevines against GDM is the application of chemical fungicides. In Spain, Carboxylic Acid Amides (CAAs) are a fungicide group currently utilized in GDM control. In P. viticola, resistance to CAAs is conferred by G1105S and G1105V mutations in the CesA3 gene. Droplet digital polymerase chain reaction (ddPCR) is an innovative technique that combines PCR and droplet microfluidics to disperse the sample into thousands of water-in-oil droplets in which an amplification reaction is individually performed. In this study, we set up a ddPCR protocol to quantify S1105 and V1105 mutations conferring resistance to CAAs in P. viticola. The optimal PCR conditions were established, and the sensitivity and precision of the protocol were assessed. Four P. viticola populations coming from commercial vineyards in northern Spain were analyzed, and different allele frequencies were found in the analyzed samples corresponding to the different fungicide management strategies, ranging from 7.72% to 100%. Knowing the level of mutated alleles allows for designing resistance management strategies suited for each location. This suggests that similar ddPCR assays could be developed for studying mutations implicated in fungicide resistance in other fungicide groups and plant pathogens.

Efficacy of using grape cane extracts against <i>Plasmopara viticola</i> under field conditions and their impact on the composition of berries and musts of <i>Vitis vinifera</i> L. cv. Riesling

Grapevine downy mildew caused by Plasmopara viticola is a deleterious vine disease currently controlled using synthetic and copper-based fungicides. Environmental concerns surrounding such fungicides necessitate sustainable alternatives like grape cane extracts. However, studies into their efficacy and effects on the product remain limited. This study aimed to assess the open-field efficacy of a novel grape cane extract formulation, alone and combined with a copper agent, against downy mildew, and to examine its impact on berry and must composition. The results were compared to standard fungicides frequently used in integrated and organic viticulture. In 2022, the grape cane extract formulation reduced downy mildew severity by 78 % on berry clusters, comparable to the maximum acceptable dose of copper for organic farming in Germany (3 kg/ha/a). Combining the grape cane extract with the copper agent was more effective than the copper agent alone, but not more effective than the grape cane extract alone. In 2023, disease development was marginal, despite artificial inoculation. Compositional differences detectable by FTIR were insignificant between musts derived from all treatments, increased copper levels were observed whenever copper had been applied. The phenolic content in freeze-dried, de-seeded berries of 2022 was significantly lower after copper (14.6 mg/g dry weight DW) and grape cane extract treatments (6.6 mg/g DW) when compared to the control (36.1 mg/g DW), with discrepancies in stilbenoid and flavan-3-ol levels in particular, as analysed by HPLC-DAD. However, these differences were not confirmed in 2023, with results showing no correlations between different treatments and phenolic contents. These findings suggest that applications of the phenolic grape cane extract do not lead to artificially altered levels or relevant residues of the active constituents; i.e., the phenolic compounds in the product. In brief, grape cane extracts might represent a promising natural alternative to controlling grapevine downy mildew, particularly in organic viticulture, which, to date, heavily relies on (eco-)toxic copper-pesticides. Further multi-year studies including wine analyses are warranted to follow the entire flow towards the final product.

Time-Course Transcriptome Analysis Reveals Distinct Transcriptional Regulatory Networks in Resistant and Susceptible Grapevine Genotypes in Response to White Rot.

Grapevine (Vitis vinifera L.) is a globally significant economic crop. However, its widely cultivated varieties are highly susceptible to white rot disease. To elucidate the mechanisms of resistance in grapevine against this disease, we utilized time-ordered gene co-expression network (TO-GCN) analysis to investigate the molecular responses in the grapevine varieties 'Guifeimeigui' (GF) and 'Red Globe' (RG). An assessment of their resistance demonstrated that GF is highly resistant to white rot, whereas RG is highly susceptible. We conducted transcriptome sequencing and a TO-GCN analysis on leaf samples from GF and RG at seven time points post-infection. Although a significant portion of the differentially expressed genes related to disease resistance were shared between GF and RG, the GF variety rapidly activated its defense mechanisms through the regulation of transcription factors during the early stages of infection. Notably, the gene VvLOX3, which is a key enzyme in the jasmonic acid biosynthetic pathway, was significantly upregulated in GF. Its upstream regulator, Vitvi08g01752, encoding a HD-ZIP family transcription factor, was identified through TO-GCN and yeast one-hybrid analyses. This study provides new molecular insights into the mechanisms of grapevine disease resistance and offers a foundation for breeding strategies aimed at enhancing resistance.

DMFGAN: a multifeature data augmentation method for grape leaf disease identification.

The use of deep learning techniques to identify grape leaf diseases relies on large, high-quality datasets. However, a large number of images occupy more computing resources and are prone to pattern collapse during training. In this paper, a depth-separable multifeature generative adversarial network (DMFGAN) was proposed to enhance grape leaf disease data. First, a multifeature extraction block (MFEB) based on the four-channel feature fusion strategy is designed to improve the quality of the generated image and avoid the problem of poor feature learning ability of the adversarial generation network caused by the single-channel feature extraction method. Second, a depth-based D-discriminator is designed to improve the discriminator capability and reduce the number of model parameters. Third, SeLU activation function was substituted for DCGAN activation function to overcome the problem that DCGAN activation function was not enough to fit grape leaf disease image data. Finally, an MFLoss function with a gradient penalty term is proposed to reduce the mode collapse during the training of generative adversarial networks. By comparing the visual indicators and evaluation indicators of the images generated by different models, and using the recognition network to verify the enhanced grape disease data, the results show that the method is effective in enhancing grape leaf disease data. Under the same experimental conditions, DMFGAN generates higher quality and more diverse images with fewer parameters than other generative adversarial networks. The mode breakdown times of generative adversarial networks in training process are reduced, which is more effective in practical application.

Effects of three elicitors on primary metabolism six days after treatment in healthy <i>Vitis vinifera</i> leaves and eight days after treatment in healthy and downy mildew-inoculated leaves

Elicitors can be used to reduce the application of conventional pesticides against grapevine diseases; however, they may disrupt plant primary metabolism. The long-term effects (more than 6 days after treatment) of applying plant defence stimulators (PDS) to protect grapevine from Plasmopara viticola were investigated. We studied the effect of three PDS (acibenzolar-S-methyl/ASM, potassium phosphonate/PHOS, methyl jasmonate/MeJA) and one surfactant (Triton) on gene expression and metabolite production in leaves of Vitis vinifera cv. Cabernet-Sauvignon before or after their inoculation with P. viticola. The molecular and biochemical results show the impact of these PDS on grapevine metabolism more than 6 days after treatment, and after inoculation. High-throughput q-RT-PCR revealed that sixty of the primary metabolism genes (ion homeostasis and hormones pathways) were modulated by all treatments, some modulations being specific to a given PDS. Meanwhile, 1H NMR studies revealed variations in metabolite abundances (amines, amino acids, organic acids, polyphenols and sugars), with some being common to all treatments (organic acid increase) and others specific to a single one. By combining two methodological approaches, it was possible to determine the specific effects of each PDS on Vitis. All PDS-induced resistance involved modulation of the primary metabolism. This innovative approach can be extended to vineyard studies in order to help better understand the variability of PDS effects in natura.

Revisiting the epidemiological role of a native vector in Northern California vineyards

Abstract Effective disease management hinges on an accurate understanding of the ecological and epidemiological underpinnings of the pathosystem. New epidemics may prompt consideration of whether knowledge gaps or changes to the pathosystem warrant revision of management strategies. Pierce’s disease of grapevines is highly episodic in coastal Northern California vineyards, with modest incidence in most years punctuated by occasionally severe epidemics. To better understand what was driving a developing epidemic in the region, we revaluated what is known about the ecology and epidemiological role of the dominant vector, the blue-green sharpshooter Graphocephala atropunctata. We monitored vector spatiotemporal dynamics at 32 vineyards over three years, surveyed plant community composition in the adjacent habitat to understand its link to vector recruitment, and quantified patterns of natural infectivity for the pathogen Xylella fastidiosa. Overall, the results were consistent with past studies of G. atropunctata ecology. For example, the scale of dispersal from source habitat and seasonal patterns in activity were generally similar to those documented in prior studies. The results also confirmed the influence of adjacent plant community composition on G. atropunctata activity in vineyards, and the role of riparian habitat and select plant taxa as vector sources. Nonetheless, further consideration of the epidemiological significance of certain features of the pathosystem may be warranted, especially those related to seasonality in X. fastidiosa infection in vectors. A marked increase in infected G. atropunctata late in the season likely reflects pathogen acquisition from infected grapevines, which may have implications for disease management strategies.

Gone-wild grapevines in forests host phytoplasma genotypes linked to grapevine’s flavescence dorée epidemics in cultivated vineyards and competent vectors

Abstract“Flavescence dorée” (FD) is a quarantine grapevine disease associated with FD phytoplasmas (FDp). In Switzerland, FD was identified in 2004 in the southernmost part of Canton Ticino (TI) and then rapidly propagated throughout the entire regional winegrowing area despite the mandatory control measures. The reported widespread distribution of gone-wild grapevines (GWGV) in TI raised the hypothesis of a potential role of GWGV as an FDp reservoir and as a habitat for FDp vectors. To test this assumption, GWGV and FDp vectors were sampled in 13 plots to attest their infection status and compare the FDp genetic profiles. The primary (Scaphoideus titanus) and best-candidate alternative (Orientus ishidae) vectors were collected throughout the season and were found in moderate to high abundance in all the study area. The infection rate of both GWGV and S. titanus followed the historical gradient of S. titanus arrival and dispersal in TI with a clear geographic distinction between the southern and northern part of TI. Interestingly, the rate measured for S. titanus was similar to that observed in highly FD-infested cultivated vineyards. Moreover, the genetic profiles of the infected GWGV and S. titanus samples were identical to those commonly observed in cultivated vineyards (map M54). Importantly, four specimens of O. ishidae were also found harboring the same genotype. This study emphasizes the importance of GWGV (and abandoned vineyards) and alternative vectors for the FD epidemics in FD-infested regions, as well as a potential origin for FD outbreaks in areas currently designated as FDp-free.

Environmental benefits of ozonated water for sustainable grapevine disease control: A life cycle and carbon sequestration analysis

The oxidative capacity of ozone makes it a highly effective biocide, widely used in the food and processing industry, as well as in drinking water plants. In a context of tighter restrictions on the use of synthetic plant protection products at the regulatory level, wineries are looking for alternative methods to control diseases, making the application of ozonated water an option to consider. To determine the environmental sustainability of this alternative vineyard disease control treatment, an environmental impact assessment was conducted using the Life Cycle Assessment (LCA) methodology. The assessment was carried out in a vineyard located in the D.O. Rías Baixas of Galicia, located in northwestern Spain. The analysis was conducted on the basis of two functional units: i) 1 kg of grapes and ii) 1 ha of land managed and using a cradle-to-gate boundary system. Ten impact categories were assessed using the ReCiPe method, except for the water scarcity indicator, which was quantified using AWARE.The environmental sustainability of the vineyard was further analyzed by measuring its carbon sequestration potential to obtain a more complete environmental profile. The RothC-26.3 model was chosen to estimate absolute carbon sequestration and annual sequestration rate from 2020 to 2040. Since the ozone-only scenarios lost all harvest, no environmental assessment was performed for such scenarios. For the remaining scenarios, the findings suggest that those using a combination of ozonated water and fungicides have the worst environmental performance due to notable reductions in grape yield and more frequent disease control interventions, particularly in certain scenarios. When evaluating environmental performance per hectare of land managed, the scenario using ozonated water with a limited number of disease control interventions exhibited the most favorable environmental profile, primarily due to reduced use of fungicides and disease control passes. In addition, the main contributors to the vineyard environmental profile identified were diesel fuel combustion during field operations, fertilizer use and production, and irrigation. In addition, the research indicates that the vineyard sequesters carbon annually, but this alone is insufficient to offset its greenhouse gas emissions. However, it is estimated that through the application of more appropriate soil management practices, the vineyard could achieve carbon neutrality and potentially increase soil carbon stocks over time.

Ectopic and transient expression of VvDIR4 gene in Arabidopsis and grapes enhances resistance to anthracnose via affecting hormone signaling pathways and lignin production.

DIR (Dirigent) proteins play important roles in the biosynthesis of lignin and lignans and are involved in various processes such as plant growth, development, and stress responses. However, there is less information about VvDIR proteins in grapevine (Vitis vinifera L). In this study, we used bioinformatics methods to identify members of the DIR gene family in grapevine and identified 18 VvDIR genes in grapevine. These genes were classified into 5 subfamilies based on phylogenetic analysis. In promoter analysis, various plant hormones, stress, and light-responsive cis-elements were detected. Expression profiling of all genes following Colletotrichum gloeosporioides infection and phytohormones (salicylic acid (SA) and jasmonic acid (JA)) application suggested significant upregulation of 17 and 6 VvDIR genes, respectively. Further, we overexpressed the VvDIR4 gene in Arabidopsis thaliana and grapes for functional analysis. Ectopic expression of VvDIR4 in A. thaliana and transient expression in grapes increased resistance against C. gloeosporioides and C. higginsianum, respectively. Phenotypic observations showed small disease lesions in transgenic plants. Further, the expression patterns of genes having presumed roles in SA and JA signaling pathways were also influenced. Lignin contents were measured before and after C. higginsianum infection; the transgenic A. thaliana lines showed higher lignin content than wild-type, and a significant increase was observed after C. higginsianum infection. Based on the findings, we surmise that VvDIR4 is involved in hormonal and lignin synthesis pathways which regulate resistance against anthracnose. Our study provides novel insights into the function of VvDIR genes and new candidate genes for grapevine disease resistance breeding programs.

High-Performance Grape Disease Detection Method Using Multimodal Data and Parallel Activation Functions

This paper introduces a novel deep learning model for grape disease detection that integrates multimodal data and parallel heterogeneous activation functions, significantly enhancing detection accuracy and robustness. Through experiments, the model demonstrated excellent performance in grape disease detection, achieving an accuracy of 91%, a precision of 93%, a recall of 90%, a mean average precision (mAP) of 91%, and 56 frames per second (FPS), outperforming traditional deep learning models such as YOLOv3, YOLOv5, DEtection TRansformer (DETR), TinySegformer, and Tranvolution-GAN. To meet the demands of rapid on-site detection, this study also developed a lightweight model for mobile devices, successfully deployed on the iPhone 15. Techniques such as structural pruning, quantization, and depthwise separable convolution were used to significantly reduce the model’s computational complexity and resource consumption, ensuring efficient operation and real-time performance. These achievements not only advance the development of smart agricultural technologies but also provide new technical solutions and practical tools for disease detection.

Early prediction of grape disease attack using a hybrid classifier in association with IoT sensors

Machine learning with IoT practices in the agriculture sector has the potential to address numerous challenges encountered by farmers, including disease prediction and estimation of soil profile. This paper extensively explores the classification of diseases in grape plants and provides detailed information about the conducted experiments. It is important to keep track of each crop's current environmental conditions because different environmental conditions, such as humidity, temperature, moisture, leaf wetness, light intensity, wind speed, and wind direction, can affect or sustain the quality of a crop. IoT will increasingly be used in precision agriculture and smart environments to detect, gather, and share data about environmental occurrences. The environmental factor that is active at all times and has an effect on a crop from its cultivation to harvest. With the aid of an IoT, we will monitor the following factors: temperature, humidity, and leaf wetness, all of which have an impact on the overall quality and lifespan of grapes. A Self-created database of weather parameter using sensors is introduced in this article. It consists of 5 categories with a total of 10,000 records. Here, experiment has been carried out using our dataset to predict grape diseases on various machines learning algorithm. The system receives overall accuracy of 98.25 % for Powdery Mildew, 98.85 % for Downy Mildew and 93.95 % for Bacterial Leaf Spot.

A bioassay that yields quantifiable symptoms of cucurbit yellow vine disease caused by Serratia marcescens.

Cucurbit yellow vine disease (CYVD), which is caused by the gram-negative bacterium Serratia marcescens and transmitted by squash bugs (Anasa tristis DeGeer), is a devastating disease of cucurbit crops that is emerging rapidly in the eastern half of the U.S. The lack of a robust pathogenicity assay for CYVD in the laboratory has hampered functional tests using genomic sequences to investigate the biology of this phytopathogen. In this study we developed and validated a bioassay that yielded consistent and quantifiable CYVD symptoms on squash in the lab. We compared inoculation by wounding with a multipronged floral pin frog to inoculation by injection in which a needle was moved in and out of the stem multiple times in each of multiple piercings to mimic the feeding behavior of squash bugs. We found that inoculation by needle injection of ≥108 CFU/ml of S. marcescens into the stem of squash (Cucurbita pepo) plants at the cotyledon growth stage reproducibly induced CYVD symptoms, whereas injecting 106 or 107 CFU/ml did not. Additionally, we found that S. marcescens induced symptoms on all of the squash cultivars tested, and induced symptoms that have not been previously reported, including stem elongation and leaf cupping. In short, through our injection approach of mimicking the natural process of S. marcescens transmission by squash bug feeding, we obtained robust and quantifiable CYVD symptoms. This laboratory bioassay provides a crucial tool for investigating the biology and pathology of this emerging pathogen and for plant breeding screens aimed at combatting CYVD.

Assessing the Capacity of High-resolution Commercial Satellite Imagery for Grapevine Downy Mildew Detection and Surveillance in New York state.

Grapevine downy mildew (GDM), caused by the oomycete Plasmopara viticola, can cause 100% yield loss and vine death under conducive conditions. High resolution multispectral satellite platforms offer the opportunity to track rapidly spreading diseases like GDM over large, heterogeneous fields. Here, we investigate the capacity of PlanetScope (3 m) and SkySat (50 cm) imagery for season-long GDM detection and surveillance. A team of trained scouts rated GDM severity and incidence at a research vineyard in Geneva, NY, USA from June to August of 2020, 2021, and 2022. Satellite imagery acquired within 72 hours of scouting was processed to extract single-band reflectance and vegetation indices (VIs). Random forest models trained on spectral bands and VIs from both image datasets could classify areas of high and low GDM incidence and severity with maximum accuracies of 0.85 (SkySat) and 0.92 (PlanetScope). However, we did not observe significant differences between VIs of high and low damage classes until late July-early August. We identified cloud cover, image co-registration, and low spectral resolution as key challenges to operationalizing satellite-based GDM surveillance. This work establishes the capacity of spaceborne multispectral sensors to detect late-stage GDM and outlines steps towards incorporating satellite remote sensing in grapevine disease surveillance systems.

Diaporthe foeniculina and D. eres, in addition to D. ampelina, may cause Phomopsis cane and leaf spot disease in grapevine.

Phomopsis cane and leaf spot (PCLS) disease, affecting grapevines (Vitis vinifera and Vitis spp.), has been historically associated with Diaporthe ampelina. Typical disease symptoms, comprising bleaching and black pycnidia, have also been associated with other Diaporthe spp. In this study, we conducted a molecular identification of the Diaporthe isolates isolated from grapevine canes from different geographic areas of southern Europe showing PCLS symptoms. Then, we investigated their morphological characteristics (including mycelium growth and production of pycnidia and alpha and beta conidia) in response to temperature. Finally, we artificially inoculated grapevine shoots and leaves with a subset of these isolates. Based on our results, PCLS etiology should be reconsidered. Though D. ampelina was the most crucial causal agent of PCLS, D. eres and D. foeniculina were also pathogenic when inoculated on green shoots and leaves of grapevines. However, D. rudis was not pathogenic. Compared to D. ampelina, D. eres and D. foeniculina produced both pycnidia and alpha conidia at lower temperatures. Thus, the range of environmental conditions favorable for PCLS development needs to be widened. Our findings warrant further validation by future studies aimed at ascertaining whether the differences in temperature requirements among species are also valid for conidia-mediated infection since it could have substantial practical implications in PCLS management.

WITHDRAWN: Grape defense against gray mold involves VvBZR1-mediated autophagy

Brassinosteroids (BRs) are a class of polyhydroxylated steroidal phytohormones that effectively affect the disease resistance in grape. However, the molecular mechanism of BR signaling networks responsible for activation of host defense against gray mold infection remained to be elucidated. The induced resistance mechanism of eBR treatment on table grapes (Vitis vinifera L. cv. Thompson Seedless) was conducted by an artificial inoculation trial. Grape berries were soaked in 0.5 mg L-1 24-epibrassinolide solution, and Botrytis cinerea suspension was injected after 6 hours. We reported a novel defense mechanism that BR-regulated autophagy in grape berry against B. cinerea. Exogenous application of 24-epibrassinolide (eBR) enhanced the grape disease resistance. The eBR-treated berries activated an oxidation-reduction (redox), polyamines metabolism, and autophagy during Botrytis infection. Transcript of BR signaling pathway genes were up-regulated within 12 h. In addition, transcriptome analysis in EBR-treated grapes infected with gray mold showed that the differentially expressed genes (DEGs) were enriched in the metabolic pathway of BR signaling pathway and autophagy. Meanwhile, the endogenous BR, SA and JA accumulated transiently. Overexpressing and silencing VvBZR1 in grape significantly affected oxidation, autophagy, and defense response. DNA affinity purification sequencing (Dap-seq), Yeast one-hybrid assay (Y1H) and dual luciferase assays (LUC) verified VvBZR1 transcriptionally regulated the autophagy related gene VvATG18a. Overexpressing VvATG18a improved the resistance of grapes to gray mold. Overall, this study sheds light on the immune mechanisms underlying the involvement of the BR signal transduction pathway in grape innate immunity, highlighting the pivotal role of VvBZR1-mediated autophagy in enhancing disease resistance.

Effect of temperature on the development of fruiting bodies of Phaeoacremonium minimum and Phaeomoniella chlamydospora on grapevine cuttings in vitro, and survival of both pathogens in vineyards.

In this study, isolates of Phaeoacremonium minimum and Phaeomoniella chlamydospora, fungal pathogens associated with Petri and esca diseases of grapevine, were used to determine the effect of temperature on the development of their fruiting bodies in vitro. Perithecia of Pm. minimum and pycnidia of Pa. chlamydospora were induced at 5, 10, 15, 20, 25 and 30ºC on pieces of 1-year-old grapevine cuttings of 110 Richter rootstock, which were incubated for 45 days under continuous white light. Both species were able to produce abundant fruiting bodies at temperatures ranging from 15 to 25ºC, but Pm. minimum produced more perithecia at 25ºC and Pm. chlamydospora produced more pycnidia at 20ºC. At 30ºC, only very few reproductive structures were observed. Calculated optimal temperatures ranged from 23.3ºC to 25.6ºC, and equations providing a proper description of temperature effect on Pm. minimum and Pa. chlamydospora fruiting bodies development were obtained. Moreover, the development of fruiting bodies and the survival of both pathogens on artificially inoculated grapevine cuttings was investigated in two vineyards. No fruiting bodies were observed during the vineyard experiments, but both fungal species were systematically recovered by fungal isolation from the cuttings. Differences in pathogen survival based on incidence data were observed relative to the species, location and time of exposure, and generalized linear-mixed models analysis showed a progressive reduction of inoculum viability with time. The present research increases our knowledge about the biology and epidemiology of Pm. minimum and Pa. chlamydospora, being particularly useful to improve epidemiological models that could be developed for Petri and esca diseases prediction.

Whole Genome Sequencing of Bacillus velezensis AMR25, an Effective Antagonist Strain against Plant Pathogens.

The most serious problems for cultivated grapes are pathogenic microorganisms, which reduce the yield and quality of fruit. One of the most widespread disease of grapes is "gray mold", caused by the fungus Botrytis cinerea. Some strains of Bacillus, such as Bacillus halotolerans, Bacillus amyloliquefaciens, and Bacillus velezensis, are known to be active against major post-harvest plant rots. In this study, we showed that the endophytic bacteria B. velezensis strain AMR25 isolated from the leaves of wild grapes Vitis amurensis Rupr. exhibited antimicrobial activity against grape pathogens, including B. cinerea. The genome of B. velezensis AMR25 has one circular chromosome with a length of 3,909,646 bp. with 3689 open reading frames. Genomic analysis identified ten gene clusters involved in the nonribosomal synthesis of polyketides (macrolactin, bacillene, and difficidin), lipopeptides (surfactin, fengycin, and bacillizin), and bacteriocins (difficidin). Also, the genome under study contains a number of genes involved in root colonization, biofilm formation, and biosynthesis of phytohormones. Thus, the endophytic bacteria B. velezensis strain AMR25 shows great promise in developing innovative biological products for enhancing plant resistance against various pathogens.

Broad-Spectrum Efficacy and Modes of Action of Two Bacillus Strains against Grapevine Black Rot and Downy Mildew.

Black rot (Guignardia bidwellii) and downy mildew (Plasmopara viticola) are two major grapevine diseases against which the development of efficient biocontrol solutions is required in a context of sustainable viticulture. This study aimed at evaluating and comparing the efficacy and modes of action of bacterial culture supernatants from Bacillus velezensis Buz14 and B. ginsengihumi S38. Both biocontrol agents (BCA) were previously demonstrated as highly effective against Botrytis cinerea in grapevines. In semi-controlled conditions, both supernatants provided significant protection against black rot and downy mildew. They exhibited antibiosis against the pathogens by significantly decreasing G. bidwellii mycelial growth, but also the release and motility of P. viticola zoospores. They also significantly induced grapevine defences, as stilbene production. The LB medium, used for the bacterial cultures, also showed partial effects against both pathogens and induced plant defences. This is discussed in terms of choice of experimental controls when studying the biological activity of BCA supernatants. Thus, we identified two bacterial culture supernatants as new potential biocontrol products exhibiting multi-spectrum antagonist activity against different grapevine key pathogens and having a dual mode of action.

Modern Spraying Techniques For Grape Vineyards: A Review

During crop production, the most crucial techniques are being used for plant protection. Applying pesticides requires much more expertise and understanding than any other agricultural job, regardless of the crop being treated or the tools utilised. This is particularly applied to insect, disease, and mite control sprays in grapevines.

Bacterial-fungicidal vine disease detection with proximal aerial images

Vine disease detection is considered one of the most crucial components in precision viticulture. It serves as an input for several further modules, including mapping, automatic treatment, and spraying devices. In the last few years, several approaches have been proposed for detecting vine disease based on indoor laboratory conditions or large-scale satellite images integrated with machine learning tools. However, these methods have several limitations, including laboratory-specific conditions or limited visibility into plant-related diseases. To overcome these limitations, this work proposes a low-altitude drone flight approach through which a comprehensive dataset about various vine diseases from a large-scale European dataset is generated. The dataset contains typical diseases such as downy mildew or black rot affecting the large variety of grapes including Muscat of Hamburg, Alphonse Lavallée, Grasă de Cotnari, Rkatsiteli, Napoca, Pinot blanc, Pinot gris, Chambourcin, Fetească regală, Sauvignon blanc, Muscat Ottonel, Merlot, and Seyve-Villard 18402. The dataset contains 10,000 images and more than 100,000 annotated leaves, verified by viticulture specialists. Grape bunches are also annotated for yield estimation. Further, tests were made against state-of-the-art detection methods on this dataset, focusing also on viable solutions on embedded devices, including Android-based phones or Nvidia Jetson boards with GPU. The datasets, as well as the customized embedded models, are available on the project webpage.2