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Most previously studies had considered that plant fungal disease spread widely and quickly by airborne fungi spore. However, little is known about the release dynamics, aerodynamic diameter, and pathogenicity threshold of fungi spore in air of the greenhouse environment. Grape gray mold is caused by Botrytis cinerea; the disease spreads in greenhouses by spores in the air and the spore attaches to the leaf and infects plant through the orifice. In this study, 120 μmol/L propidium monoazide (PMA) were suitable for treatment and quantitation viable spore by quantitative real-time PCR, with a limit detection of 8 spores/mL in spore suspension. In total, 93 strains of B. cinerea with high pathogenicity were isolated and identified from the air samples of grapevines greenhouses by a portable sampler. The particle size of B. cinerea aerosol ranged predominately from 0.65–3.3 μm, accounting for 71.77% of the total amount. The B. cinerea spore aerosols were infective to healthy grape plants, with the lowest concentration that could cause disease being 42 spores/m3. Botrytis cinerea spores collected form six greenhouse in Shandong Province were quantified by PMA-qPCR, with a higher concentration (1182.89 spores/m3) in May and June and a lower concentration in July and August (6.30 spores/m3). This study suggested that spore dispersal in aerosol is an important route for the epidemiology of plant fungal disease, and these data will contribute to the development of new strategies for the effective alleviation and control of plant diseases. [ABSTRACT FROM AUTHOR]

Botrytis cinerea is the causative agent of grey mould disease in grapes, which was linked to significant postharvest losses. This study examined three grape‐isolated yeasts (Metschnikowia aff. fructicola, Metschnikowia pulcherrima, and Hansenispora uvarum) through in vitro and in vivo tests on detached grape berries against grey mould, as well as the elucidation of their possible mechanisms of action. The antifungal mechanism of action of yeasts was determined by the lytic enzyme activity, inhibition of spore germination, biofilm activity, iron depletion, diffusible metabolites, wound‐site colonisation, mycocin, and volatile organic compounds (VOCs) production. The highest in vitro efficacy (83.13%) was observed on M. aff. fructicola, followed by M. pulcherrima (82.10%) and H. uvarum (71.66%). Metschnikowia yeasts exhibited comparable enzyme activities, including protease, β‐1,3 glucanase, gelatinase chitinase, and cellulase, while H. uvarum had a poor enzymatic activity with chitinase and gelatinase. M. aff. fructicola showed relatively higher iron depletion activity than M. pulcherrima, while M. pulcherrima outperformed via diffusible metabolites. All yeast cultures significantly reduced spore germination by at least 86%. Overall, M. aff. fructicola exhibited the highest biocontrol activity with its iron depletion, inhibition of conidial germination, biofilm formation, VOCs, and well colonisation on grape berries. M. aff. fructicola 1‐UDM outperformed all other yeasts by significantly reducing disease incidence and lesion diameter values (93.4% and 94.3%, respectively). Remarkably, H. uvarum VOCs demonstrated potential as a biofumigant for suppressing grey mould. All yeasts are well adapted to their ecological niche to bio‐protect grapes from grey mould disease. [ABSTRACT FROM AUTHOR]

This study investigated the effects of essential oils thymol, eugenol, and 1,8-cineol for the prevention of losses caused by gray mold (Botrytis cinerea Persoon) in grapevine (Vitis vinifera Linné, cv. Karaerik) under in vitro and in vivo conditions. B. cinerea isolated from diseased grapevines was identified by 18S rRNA gene sequence analysis. The effects of 2.5, 5, and 10 μL doses of essential oils (EO) on mycelial growth, germ tube elongation, and spore germination were investigated in vitro, and the lesion formation on the leaves was examined in vivo. Compared to the control, both thymol and eugenol suppressed mycelial growth, depending on the dose increase, and caused 100% inhibition at the 10 μL dose, whereas 1,8-cineole had no effect on the same parameter at either dose. Germ tube elongation was 100% inhibited by 5 and 10 μL doses of thymol and eugenol, while the same doses of 1,8-cineole inhibited it by 49% and 85%, respectively. Conidiospore germination was inhibited by 22, 45, and 72% at 2.5, 5, and 10 μL doses of thymol, respectively. Under in vivo conditions, the three EOs inhibited lesion formation on leaves, depending on the concentration increase, and inhibition ended with 100% at their 100 μL dose. In addition, thymol was found to be the most effective EO under in vivo conditions. Our results show that these EOs, which are of biological origin and non-toxic to environmental health, have the potential to be used in the control of gray mold. [ABSTRACT FROM AUTHOR]

Grapevine trunk diseases cause severe damage in grapevines. Management strategies focus on protection of grapevine pruning wounds using chemical fungicides or biological control agents. Botryosphaeria dieback, caused mainly by Lasiodiplodia spp., is one of the main trunk diseases in northwest Mexico. This study obtained endophytic bacteria and fungi from the heritage grapevine Vitis vinifera cv. ‘Mission’ for potential biological control of Botryosphaeria dieback. A collection of 135 bacterial and 37 fungal isolates were obtained and initially tested for antagonistic activity against Lasiodiplodia brasiliensis. The most promising isolates belonging to Trichoderma and Bacillus spp. were selected and characterized to determine their modes of action. Bacillus isolates produced volatile organic compounds that inhibited growth of Neofusicoccum parvum, and diffusible organic compounds with antifungal effects against L. brasiliensis and N. parvum. Trichoderma isolates produced diffusible organic compounds and were mycoparasites. In greenhouse assays, plants inoculated with three Trichoderma asperellum isolates (T20BCMX, EF09BCMX, and EF11BCMX), B. amyloliquefaciens (BEVP26BCMX) or Bacillus sp. (rbES015), applied preventively in soil, gave up to 50% smaller necrotic lesions when compared with the plants inoculated only with L. brasiliensis. In the field, plants inoculated with three Bacillus isolates (BEVP02BCMX, BEVP26BCMX, BEVP31BCMX) or five Trichoderma (T11BCMX, T15BCMX, T17BCMX, T20BCMX, and EF11BCMX) had lesions up to four times smaller than control plants inoculated only with L. brasiliensis. This study has demonstrated the potential of heritage grapevines to provide biological control agents for Botryosphaeria dieback. [ABSTRACT FROM AUTHOR]

The strains Trichoderma harzianum TH07.1-NC (TH), Aphanocladium album MX95 (AA), Pleurotus eryngii AL142PE (PE) and Pleurotus ostreatus ALPO (PO) were tested as biological limiters against Fomitiporia mediterranea Fme22.12 (FM), Phaeoacremonium minimum Pm22.53 (PM) and Phaeomoniella chlamydospora Pc22.65 (PC). Pathogens were obtained from naturally Esca-affected 'Nero di Troia' vines cropped in Grumo Appula (Puglia region, Southern Italy). The antagonistic activity of each challenge organism was verified in a dual culture. TH and PO completely overgrew the three pathogens. Partial replacement characterized PE-FM, PE-PM, PE-PC and AA-PC interactions. Deadlock at mycelial contact was observed in AA-FM and AA-PM cultures. The calculated antagonism index (AI) indicated TH and PE as moderately active antagonists (10 < AI < 15), while AA and PO were weakly active (AI < 10). The maximum value of the re-isolation index (s) was associated with deadlock among AA-PM, AA-PC and PE-FM dual cultures. The tested biological limiters were always re-isolated when PO and TH completely replaced the three tested pathogens. TH and AA confirmed their efficiencies as biological limiters when inoculated on detached canes of 'Nero di Troia' in dual combination with FM, PC and PM. Nevertheless, additional experiments should be performed for a solid conclusion, along with validation experiments in the field. [ABSTRACT FROM AUTHOR]

Grapevine flowering is an important stage in the epidemiology of Botrytis cinerea, the causal agent of gray mold disease. To prevent infection and to minimize postharvest losses, the control of this necrotrophic fungus is mainly based on chemical fungicides application. However, there is a growing interest in other control alternatives. Among them, the use of beneficial microorganisms appears as an eco-friendly strategy. This study aims to investigate the effect of Paraburkholderia phytofirmans PsJN, root-inoculated or directly sprayed on fruiting cuttings inflorescences to control B. cinerea growth. For this purpose, quantification by real time PCR of Botrytis development, direct effect of PsJN on fungal spore germination and chemotaxis were assayed. Our results showed a significant protective effect of PsJN only by direct spraying on inflorescences. Moreover, we demonstrated an inhibition exerted by PsJN on Botrytis spore germination, effective when there was a direct contact between the two microorganisms. This study showed that PsJN is positively attracted by the pathogenic fungus B. cinerea and forms a biofilm around the fungal hyphae in liquid co-culture. Finally, microscopic observations on fruit cuttings revealed a co-localization of both beneficial and pathogenic microorganisms on grapevine receptacle and stigma that might be correlated with the protective effect induced by PsJN against B. cinerea via a direct antimicrobial effect. Taking together, our findings allowed us to propose PsJN as a biofungicide to control grapevine gray mold disease. [ABSTRACT FROM AUTHOR]

The grapevine is subject to high number of fungal and viral diseases, which are responsible for important economic losses in the global wine sector every year. These pathogens deteriorate grapevine berry quality either directly via the modulation of fruit metabolic pathways and the production of endogenous compounds associated with bad taste and/or flavor, or indirectly via their impact on vine physiology. The most common and devastating fungal diseases in viticulture are gray mold, downy mildew (DM), and powdery mildew (PM), caused, respectively by Botrytis cinerea , Plasmopara viticola , and Erysiphe necator. Whereas B. cinerea mainly infects and deteriorates the ripening fruit directly, deteriorations by DM and PM are mostly indirect via a reduction of photosynthetic leaf area. Nevertheless, mildews can also infect berries at certain developmental stages and directly alter fruit quality via the biosynthesis of unpleasant flavor compounds that impair ultimate wine quality. The grapevine is furthermore host of a wide range of viruses that reduce vine longevity, productivity and berry quality in different ways. The most widespread virus-related diseases, that are known nowadays, are Grapevine Leafroll Disease (GLRD), Grapevine Fanleaf Disease (GFLD), and the more recently characterized grapevine red blotch disease (GRBD). Future climatic conditions are creating a more favorable environment for the proliferation of most virus-insect vectors, so the spread of virus-related diseases is expected to increase in most wine-growing regions. However, the impact of climate change on the evolution of fungal disease pressure will be variable and depending on region and pathogen, with mildews remaining certainly the major phytosanitary threat in most regions because their development rate is to a large extent temperature-driven. This paper aims to provide a review of published literature on most important grapevine fungal and viral pathogens and their impact on grape berry physiology and quality. Our overview of the published literature highlights gaps in our understanding of plant-pathogen interactions, which are valuable for conceiving future research programs dealing with the different pathogens and their impacts on grapevine berry quality and metabolism. [ABSTRACT FROM AUTHOR]

Botrytis cinerea, the grey mould agent, is one of the most important pathogens of grapevine, due to the great yield losses caused and the economic costs related to disease control. Ground cover plants are assumed to have a role in the complex epidemiology of the pathogen, even if no information on the genetic variability of the strains is available. In this study, a molecular epidemiology approach, based on the comparative analysis of the nucleotide sequences of multiple genes (ITS1‐ITS2, G3PDH, NEP1, NEP2, BC‐hch, and sdhB), was used to evaluate whether B. cinerea isolated from herbaceous species contributes to grey mould diffusion on grapevines. From 330 samples collected in two vineyards in Lombardy, Italy, 63 B. cinerea strains were isolated from tissues of grapevine with symptoms (50 strains) and spontaneous ground cover plants (13 strains). Capsella bursa‐pastoris, Cardamine impatiens, Lamium purpureum, and Crepis tectorum were identified as novel B. cinerea hosts. Sequence analysis and phylogeny showed that the same genotypes were present on both grapevines and herbaceous plants, with no fitness (estimated from growth and sporulation on potato dextrose agar) or pathogenicity (on grapevine leaves and berries, and tomato leaves) penalties. This confirms that ground cover plants can be a source of inoculum for B. cinerea on grapevine. Moreover, phylogenetic analysis of the BC‐hch gene allowed the identification of two genetically distinct clusters, characterized by vegetative incompatibility and different distributions of the mating types, fitness, and pathogenicity. Therefore, B. cinerea seems to be composed of two diverging subpopulations that do not differ for host specialization. [ABSTRACT FROM AUTHOR]

Grape downy mildew, caused by Plasmopara viticola (Berk. & M.A. Curtis) Berl. & De Toni 1888, is a widespread fungal disease that causes serious harm to the grape production. The long-term continuous use of chemical pesticides has caused issues with the resistance, residues and resurgence, as well as creating environmental pollution and the declining quality of the products. A biological control offers a safe and effective method to control diseases. We determined the in vitro antagonistic activity of 303 bacterial strains from infected grapevine leaves, and 12 isolates showed some level of antagonism in a detached leaf assay. Isolate SY286 reduced the disease severity in the detached leaves by 93.18%, and showed good control effects in a field assay. The scanning electron microscopy showed the damaged P. viticola cell walls when the mycelia and sporangia were treated with the fermentation liquor of isolate SY286. Furthermore, it showed an antagonistic activity against Phytophthora capsici, Phytophthora infestans, Botrytis cinerea, Fusarium oxysporum, Colletotrichum orbiculare, Trichothecium roseum, and Botryosphaeria berengeriana. The isolate was identified as Ochrobactrum sp. combined with its morphological characteristics, physiological and biochemical reactions and 16S rDNA sequence analysis, and it has the potential to control the grapevine downy mildew. [ABSTRACT FROM AUTHOR]

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Abiotic factors inducing osmotic stress can affect plant immunity and resistance against pathogen attack. Although a number of studies have characterized grapevine responses to various forms of biotic and abiotic stresses, the relationships between osmotic stress response and susceptibility of mature berries to Botrytis cinerea still remain unknown. In this study, we investigated the effects of osmotic stress and abscisic acid (ABA) on defense responses of mature grapevine berries before and after B. cinerea infection. We focused on the possible involvement of polyamines in the interaction between osmotic stress response and susceptibility to B. cinerea. We showed that osmotic stress induced by PEG or sucrose, and exogenous ABA induce transient but low defense responses, including weak expression of PR genes and phytoalexin synthesis in mature berries. This was accompanied by an upregulation of NCED2 involved in ABA biosynthesis and a large production of free polyamines. However, osmotic stress followed by B. cinerea infection primed berries for enhanced accumulation of polyamines, but slowed down the defense responses and increased susceptibility to the pathogen. A weak increase of diamine- and polyamine-oxidase activities was also recorded in stressed berries, but declined after pathogen infection. The pretreatment of stressed berries with appropriate inhibitors of diamine- and polyamine-oxidases further increased polyamine level and greatly lowered defense responses, leading to higher susceptibility to B. cinerea. These results suggest that increased polyamine titer through low activation of their oxidative degradation in grape berries may contribute at least in part to the weakening of defense responses and subsequent disease susceptibility. [ABSTRACT FROM AUTHOR]

The efficacy of a large number of plant extracts and essential oils in controlling plant diseases has been proven worldwide. Botrytis cinerea has attacked a wide host range causing severe loss in the field and at storage. In this study the antifungal efficacy of essential oils of three medicinal plants namely wild marjoram (Zataria multifolia), wild savory (perennial) (Satureja mutica) and savory (annual) (Satureja hortensis) possessing these compounds at three concentrations: 50, 100 and 200 ppm were evaluated in controlling the mycelial growth, spore germination and germ tube elongation of B. cinerea. All treatments except savory (annual) essential oil at 50 ppm showed significant differences with the control in inhibiting the mycelial growth as well as spore germination and germ tube elongation of B. cinerea (p=0.01). It was also noted that wild marjoram at 100 ppm and wild savory (perennial) essential oils at 200 ppm could completely (100%) inhibit the growth of the fungus. Essential oils from wild marjoram and wild savory had higher antifungal activity than annual savory. Their suitable formulations could be prepared and used as safe alternatives for controlling moulds of horticultural products during storage. [ABSTRACT FROM AUTHOR]

The antifungal activity of an aqueous extract (AE) and the solid fraction of a chloroform-methanol fruit pericarp extract (CME) of Sapindus mukorossi resolved in water was tested for the first time against Venturia inaequalis and Botrytis cinerea--two important fungal pathogens worldwide. In the greenhouse, a CME (1 % vol/vol) spray significantly reduced V. inaequalis symptoms and sporulation (99%) on apple seedling leaves (P ≤ 0.05). In field trials, applications of AE (1% vol/vol) reduced the disease severity of B. cinerea on grape, on average, by 63%. Extracts were fractionated by high-performance liquid chromatography and the bioefficacy of the fractions was tested in vitro. Some components of the most fungicidal fraction were identified by liquid chromatographyhigh resolution mass spectrometry as saponins: sapindoside B (accounting for ≥98% of the total constituents), hederagenin-pentosylhexoside, and oleanolic acid-hexosyl-deoxyhexosyl-hexoside. This fraction inhibited the mycelial growth of V. inaequalis and B. cinerea by 45 and 43%, respectively. [ABSTRACT FROM AUTHOR]

Botrytis cinerea, the causal agent of Botrytis bunch rot and gray mold, is the number one postharvest disease of fresh grapes in the United States. Fungicide applications are used to manage the disease, but fungicide-resistant isolates are common and postharvest losses occur annually. Host resistance is needed for long-term management of the disease. Sources of resistance in grape have been identified, but often have poor fruit quality. In this study, 27 grape lines (cultigens and species), including high fruit-quality Vitis vinifera, were evaluated for fruit and leaf susceptibility to two isolates of B. cinerea. No significant differences in virulence or pathogenicity were detected between the two isolates, but differences in disease incidence were evident among lines in leaves and berries. Most V. vinifera cultivars evaluated had high disease incidence in berries, whereas complex hybrids, Vitis aestivalus and Vitis arizonica, had low- to moderate disease incidence. Two V. vinifera breeding lines had moderate susceptibility (<50% disease) to Botrytis bunch rot when inoculated with either isolate. Only one V. vinifera line had little (<5%) to no berry or leaf disease when inoculated with either isolate. Moderate resistance (10% to 25%) was detected in Vitis spp., and a single V. vinifera line. Correlations were examined among soluble solids, leaf susceptibility, and fruit susceptibility. No correlations between soluble solids and disease susceptibility (leaves or berries) were identified, but moderate correlations between leaf and berry susceptibility were observed. Moderate resistance to Botrytis bunch rot and leaf spot were detected in Vitis breeding lines, suggesting these may be useful for developing grape cultivars with high fruit quality and resistance to B. cinerea. [ABSTRACT FROM AUTHOR]

Botrytis bunch rot is a major fungal disease of grapevines, and causes severe economic damage worldwide. Under humid climatic conditions, the development of bunch rot on grapes cannot be suppressed completely. Selection of planting material with lower bunch rot susceptibility represents one of the most efficient long-term tools in the complex bunch rot minimisation strategy. The present investigation conducted over four consecutive years (2013-2016) under the environmental conditions of the Moselle valley aimed at (i) detecting consistent differences in the bunch rot susceptibility within a group of nine commercially available Vitis vinifera L. 'White Riesling' clones, (ii) investigating potential underlying causes and (iii) deriving recommendations for 'Riesling' clone selection in practical viticulture. Disease severity and grape maturity (total soluble solids) progress could be well simulated by sigmoidal curves (R² > 0.89; P < 0.038). On average of all four years, the dates when 5 % bunch rot disease severity were reached differed significantly by 9 days between the clone with the earliest epidemic (Trier 34) and the clone with the latest epidemic (Heinz 65). Multi-annual results enabled a classification of the nine clones according to (i) their relative bunch rot susceptibility as well as (ii) their relative precocity. Based on this, practical recommendations concerning a targeted clone selection as an integral long-term tool (i) in Integrated Pest Management contributing to pesticide reduction in viticulture as well as (ii) in the viticultural climate change adaptation strategy were derived. [ABSTRACT FROM AUTHOR]

Grey mould, caused by Botrytis cinerea, is a disease severely affecting grape production in northern Italy. However, little information is available on the variability of B. cinerea populations associated with grapevine. The mode of reproduction, sensitivity to fungicides, and for the first time in Italy, the genetic structure of B. cinerea populations isolated from grapevine in a northern Italian region are reported. Botrytis cinerea isolates (317) were completely genotyped for six microsatellite loci and characterized for the presence of the transposable elements Boty and Flipper, for the mating type and for resistance to cyprodinil, fludioxonil, boscalid and fenhexamid. All the isolates were found to belong to B. cinerea Group II, indicating the absence of B. pseudocinerea in the investigated areas. The populations possess a high genotypic diversity, different frequencies of transposable elements and a mixed mode of reproduction. At a regional level, B. cinerea populations belong to a large and interconnected pathogen population that includes the major grape-growing districts. The populations were generally sensitive to fungicides, with a low proportion (8%) of isolates resistant to cyprodinil, fludioxonil and boscalid. A small genetic distance was found between B. cinerea populations. However, the populations geographically isolated from the others by a mountain range showed a small but statistically significant genetic differentiation and a different pattern of fungicide resistance. The results show that northern Italian B. cinerea populations possess a high evolutionary potential and adaptive capacity. [ABSTRACT FROM AUTHOR]

Botrytis cinerea infection of wine grapes can result in a variety of symptoms. The most common symptom is botrytis bunch rot (BBR), where infected berries rot and shrivel, and eventually produce fungal sporulation. Another symptom is slip skin, where the skins of infected ripe berries slide easily from the pulp. It is hypothesised that a reduction in osmotic potential in grape berries due to late-season rainfall leads to slip skin symptom development. Hyphal growth of B. cinerea on osmotically adjusted agar was inhibited at osmotic potentials associated with near-ripe berries. Vine sheltering was used in a research vineyard to manipulate rainfall artificially and to alter berry sugar content in Vitis vinifera Sauvignon blanc vines, with the aim of increasing osmotic potential and altering symptom expression. Both BBR and slip skin symptoms were affected by the various sheltering conditions, with sheltered vines having lower BBR and higher slip skin at harvest. [ABSTRACT FROM AUTHOR]

Fungicide resistance development in Botrytis cinerea threatens the efficacy of anilinopyrimidine (AP) fungicides, which have been used for botrytis bunch rot control in New Zealand vineyards for about 20 years. A 2016 survey of 33 vineyards in Gisborne, Hawke's Bay and Marlborough showed that the majority of 670 isolates tested in agar-based assays were sensitive to the AP cyprodinil (EC50 < 1 mg/litre), although 18% showed low-resistance (EC50 1-10 mg/litre) and 10% showed medium-resistance (EC50 >10 mg/litre). There was high cross-resistance to the APs cyprodinil and pyrimethanil. The survey also established baseline sensitivity to the succinate dehydrogenase inhibitor (SDHI) fungicide boscalid and >90% of isolates were sensitive (EC50 < 5 mg/litre). There was a low degree of cross-resistance between the SDHIs boscalid and fluopyram. There was also high sensitivity to fludioxonil (0.009 to 0.018 mg/litre) and to fenhexamid (0.49 to 0.76 mg/litre). [ABSTRACT FROM AUTHOR]

In this paper we report on the isolation and identification of three filamentous fungi from grape marc, and antifungal effect of their cell-free culture filtrates on the growth of Botrytis cinerea, causal agent of gray mold. Grape marc is a waste material that has been used as soil amendment in sustainable agriculture. Isolates originating from grape marc were identified on the basis of morphological features and internal transcribed spacer rDNA or β-tubulin gene sequencing. The presence of three different species, Penicillium paneum, Penicillium chrysogenum and Aspergillus fumigatus has been detected expressing different effect on the growth of B. cinerea. The effect of crude culture filtrates of selected fungi on B. cinerea growth was tested. Heat sensitivity of the established inhibition effect was examined by autoclaving the crude culture filtrate prior to testing. Additional aim was to determine whether antifungal effect was influenced by previous exposure to B. cinerea in dual liquid cultures. Crude culture filtrate of A. fumigatus K16/2 showed the lowest suppression of B. cinerea growth. A maximal percentage inhibition achieved within the study was 38.2%, 39.8% and 23.8 for crude filtrates of P. paneum K7/1, P. chrysogenum K11/1 and A. fumigatus K16/2, respectively. Presence of B. cinerea in dual liquid culture induced significant increase in antifungal capacity of the culture filtrates in comparison to pure culture filtrates of the chosen isolates. The antifungal activity of all of the isolates' culture filtrates retained after heat treatment suggesting the presence of some thermostable antifungal metabolites. The results indicate the complexity and specificity of the interaction between filamentous fungi and B. cinerea. Grape marc is a good source for isolation od B. cinerea fungal antagonists and their antifungal metabolites. Specificity of fungal-fungal interactions suggests that further research on the antagonistic mechanisms and factors affecting them should be studied separately for each pair of antagonists. [ABSTRACT FROM AUTHOR]

The production of botrytised wines involves grapes with high sugar concentration and complex aromas caused by the presence of noble rot. The aim of this paper was to characterise botrytised grapes on a physico-chemical basis and therefore identify markers of its evolution. Colour analysis, compression and puncture tests and phenolic profiles were performed in order to identify the potential markers and discriminating tools for the presence of the fungus. Chenin blanc grapes from two parcels in Loire Valley (France) were sampled during a 4-week period. Significant changes of phenolic composition like the total polyphenol which decreases up to 40 % were observed as B. cinerea was more advanced on the berries. Myricetin a compound that has not been reported before in white grapes was found only in highly affected berries. At the same time as the level of infection increases, the presence of the fungus seems to induce, from one side, an increase of catechin, epicatechin and epicatechin gallate, and from the other side, the decrease in caftaric acid, coutaric acid, quercetin-3 glucoside and kaempferol-3 glucoside. Puncture tests appeared to be the more reliable mechanical tool to differentiate between infection levels by itself; however, the combination of puncture and compression tests with colour showed a more significant and clear differentiation. This combination appeared to be the most adequate for stablish markers of noble rot evolution in the conditions studied. A decrease in mechanical resistance of berries' skin (measured by the maximum puncture force required for skin rupture) was observed during infection. These results on botrytised Chenin grapes are new and provide a novel approach for an objective measurement of noble rot in Chenin grapes. [ABSTRACT FROM AUTHOR]

Noble rot results from exceptional infections of ripe grape (Vitis vinifera) berries by Botrytis cinerea. Unlike bunch rot, noble rot promotes favorable changes in grape berries and the accumulation of secondary metabolites that enhance wine grape composition. Noble rot-infected berries of cv Sémillon, a white-skinned variety, were collected over 3 years from a commercial vineyard at the same time that fruit were harvested for botrytized wine production. Using an integrated transcriptomics and metabolomics approach, we demonstrate that noble rot alters the metabolism of cv Sémillon berries by inducing biotic and abiotic stress responses as well as ripening processes. During noble rot, B. cinerea induced the expression of key regulators of ripening-associated pathways, some of which are distinctive to the normal ripening of red-skinned cultivars. Enhancement of phenylpropanoid metabolism, characterized by a restricted flux in white-skinned berries, was a common outcome of noble rot and red-skinned berry ripening. Transcript and metabolite analyses together with enzymatic assays determined that the biosynthesis of anthocyanins is a consistent hallmark of noble rot in cv Sémillon berries. The biosynthesis of terpenes and fatty acid aroma precursors also increased during noble rot. We finally characterized the impact of noble rot in botrytized wines. Altogether, the results of this work demonstrated that noble rot causes a major reprogramming of berry development and metabolism. This desirable interaction between a fruit and a fungus stimulates pathways otherwise inactive in white-skinned berries, leading to a greater accumulation of compounds involved in the unique flavor and aroma of botrytized wines. [ABSTRACT FROM AUTHOR]

A total of 41 endophytic bacterial strains were assessed for antimicrobial activity against indicator organisms in a preliminary screening. Of these, two bacterial strains that showed a strong antimicrobial activity were selected and identified asBacillus subtilis(Bs1 and Bs2). The activities of Bs1 and Bs2 strains and different bile acids were assessed againstBotrytis cinereaandPlasmopara viticolagrapevine pathogens using in vitro and in vivo methods. Bs1 and Bs2 strains strongly inhibitedBotrytis cinereagrowth in vitro. The cell-free filtrates of both strains also reducedBotrytis cinereagrowth. Chenodeoxycholic acid (CDCA) inhibitedBotrytis cinereagrowth in potato dextrose agar medium and suppressedP. viticoladevelopment in grapevine leaf discs. Epifluorescence microscopy observations revealed an important restriction ofP. viticoladevelopment at the vesicle stage. In addition, CDCA markedly reduced the ability ofP. viticolasporangia to release zoospores in vitro, confirming the direct fungicidal effect of this bile acid. [ABSTRACT FROM AUTHOR]

A mechanistic model for Botrytis cinerea on grapevine was developed. The model, which accounts for conidia production on various inoculum sources and for multiple infection pathways, considers two infection periods. During the first period (“inflorescences clearly visible” to “berries groat-sized”), the model calculates: i) infection severity on inflorescences and young clusters caused by conidia (SEV1). During the second period (“majority of berries touching” to “berries ripe for harvest”), the model calculates: ii) infection severity of ripening berries by conidia (SEV2); and iii) severity of berry-to-berry infection caused by mycelium (SEV3). The model was validated in 21 epidemics (vineyard × year combinations) between 2009 and 2014 in Italy and France. A discriminant function analysis (DFA) was used to: i) evaluate the ability of the model to predict mild, intermediate, and severe epidemics; and ii) assess how SEV1, SEV2, and SEV3 contribute to epidemics. The model correctly classified the severity of 17 of 21 epidemics. Results from DFA were also used to calculate the daily probabilities that an ongoing epidemic would be mild, intermediate, or severe. SEV1 was the most influential variable in discriminating between mild and intermediate epidemics, whereas SEV2 and SEV3 were relevant for discriminating between intermediate and severe epidemics. The model represents an improvement of previous B. cinerea models in viticulture and could be useful for making decisions about Botrytis bunch rot control. [ABSTRACT FROM AUTHOR]

Plant Pectin Methylesterases (PMEs) represent a group of tissue-specific and developmentally regulated proteins. The gene family is involved in the plant cell wall (CW) remodelling process, by the control of the degree of cell wall pectin methylesterification. Pectin methylesterification also influence the susceptibility to pathogens as Botrytis cinerea (Bc), a necrotrophic fungus responsible of the Botrytis bunch rot in grapevine. In Botrytis, PME as well as other CW degrading enzymes have been identified as virulence factors. To further characterize the PME gene family and its role in the Botrytis bunch rot, the latest genome assembly and annotation were revised and through sequence homology search, a total of 63 PME domain containing proteins were identified, 16 more than a previous identification in grapevine. The in-silico analyses of the family by means of the Vitis gene expression database VESPUCCI as well as Aggregated Gene Co-expression Network approach (AggGCNs) allowed us to identify and enrich gene co-expression modules and build gene coexpression networks. Interestingly, one of the co-expression modules showed a high modulation in presence of Botrytis cinerea infection and particular attention was paid to it. To investigate the contribution of the genes of that module, their expression level in different organs and developmental stages from two grapevine cultivars with divergent Bc susceptibility was investigated. Furthermore, berries were artificially infected with Bc at mature stage to evaluate PME gene expression level and their possible role in the grapevine bunch rot susceptibility. The results obtained contribute to characterize the grapevine PME gene family and the role of specific members in the grapevine-Bc interaction and to select PME genes candidate to the control of Botrytis bunch rot in grapevine. [ABSTRACT FROM AUTHOR]

The effect of temperature and wetness duration on infection of Vitis vinifera inflorescences (from "inflorescence clearly visible" to "end of flowering" stages) and young berry clusters (at "fruit swelling" and "berries groat-sized" stages) by Botrytis cinerea was investigated. Artificial inoculations were carried out using conidial suspensions of eight B. cinerea strains belonging to the transposon genotypes transposa and vacuma. Infection incidence was significantly affected by strain but not by transposon genotype (transposon genotype accounted for only 6.5% of the variance). Infection incidence was also affected by the interaction between strain and growth stage of the inflorescence or berry cluster (overall accounting for approximately 57% of the experimental variance). Thus, under our experimental conditions, the ability to cause infection was a strain rather than a transposon genotype attribute. Across all strains, infection incidence was lowest when inflorescences were clearly visible or fully developed, highest at flowering (from beginning to end of flowering), and intermediate at the postflowering fruit stages (fruit swelling and berries groat-sized). One transposa strain, however, was highly virulent on all grapevine growth stages tested. The effects of temperature and wetness duration on infection incidence were similar for all fungal strains and grapevine growth stages; infection incidence was highest at 20°C and lowest at 30°C, and was also low at 5°C. Similar results were obtained for mycelial growth and conidial germination. Based on the pooled data for all strains and grapevine growth stages, an equation was developed that accounted for the combined effects of temperature and wetness duration on relative infection incidence. This equation should be useful for developing decision-making systems concerning B. cinerea control at early grapevine growth stages. [ABSTRACT FROM AUTHOR]

Fruit rots are some of the most important diseases of grape and strawberry. With recent public concern regarding pesticide residues on fruit, there is a need for alternative disease management practices that will reduce the risk to consumers. The main aim of this study was to investigate the effectiveness of the commercial product BOTRY-Zen (active ingredientUlocladium oudemansii[U3 strain]) to control strawberry and grape fruit rots. BOTRY-Zen at 6 g/L reduced significantly the percentage of rotted fruit in comparison with the untreated control. However, its effectiveness was significantly less than that of the fungicide Switch 25/37.5 WG (fludioxonil: cyprodinil) at a rate of 1 g/L (recommended by producer). There was no significant difference between the BOTRY-Zen at rate of 4 g/L and untreated plants. The results of this study showed that the commercial product BOTRY-Zen, at 6 g/L, could be a useful tool to control fruit rots of strawberry and grape in biological fruit production systems. [ABSTRACT FROM AUTHOR]

Botrytis bunch rot ( BBR), caused by Botrytis cinerea, degrades wine grapes during ripening, even though infection can occur as early as flowering. Effective BBR management requires knowledge of whether some stages of fruit development are more important than others in relation to infection and BBR severity at harvest. Bunches of Vitis vinifera ' Sauvignon blanc' and/or ' Pinot noir' were inoculated in two vineyard trials and one glasshouse trial with nitrate non-utilizing ( nit) mutant strains at three phenological stages: early flowering, pre-bunch closure ( PBC) and veraison. Isolates recovered from symptomless berries at veraison and from bunches with symptoms at harvest were screened to measure the incidence of the nit strains used in the inoculations. It was found that latent infections, which resulted in BBR at harvest, could become established at all three phenological stages and no single stage was associated with greater latent incidence or harvest severity than any other stage. It was concluded that a proportion of BBR at harvest resulted from the expression of latent infections that had accumulated throughout the season. However, the time between infection and BBR symptom expression in near-ripe grape berries was sufficiently short for polycyclic secondary infection to also contribute to epidemic development. [ABSTRACT FROM AUTHOR]

Grapes kept after harvest for withering in drying fruit rooms ( fruttaio) are highly susceptible to Botrytis cinerea infection. A taxonomically undefined isolate (B83) was identified during a survey of B. cinerea populations in these specific environments. This isolate yielded negative results in B. cinerea-specific PCRs and displayed a different colony morphology on potato dextrose agar. Based on this data, the isolate underwent a taxonomic investigation. Sequencing of the ITS-5·8S- ITS2 region indicated that the isolate belongs to the Botrytis genus. IGS- RFLP analysis revealed that Botrytis sp. B83 was a different haplotype from genotypes of indigenous B. cinerea strains. Comparative sequence analysis of three housekeeping genes, G3 PDH, HSP60 and RPB2, showed that the isolate constitutes a taxon related to Botrytis aclada, distant from B. cinerea. A phylogenetic tree built with NEP genes was in agreement with the combined tree built with G3 PDH, HSP60 and RPB2 sequences. Botrytis sp. B83 is morphologically similar to B. aclada. Conversely, its host range indicates that it is polyphagous like B. cinerea, despite its lower virulence. This study provides evidence for the existence of a new species of Botrytis. Nevertheless, the description of only a single isolate and the need for further information on genetic divergence, reproductive isolation and host preference, prevent the classification and formal description of a new taxon. [ABSTRACT FROM AUTHOR]

Airborne Botrytis cinerea conidia concentration was monitored using a new qPCR assay in strawberry, raspberry and grape plantings in 2010, 2011 and 2012. Airborne inoculum progress curves (IPCs) were constructed and analysed using the maximum ACC (Ymax), ACC during the flowering period (Yf), and area under the IPC (AUIPCstd) and descriptors derived from fitting growth models. The structure of IPCs was examined by conducting multivariate principal component analyses. The dimensionality of the data was reduced to two principal components (PCs) accounting for 86·12% of the variation. All descriptors derived from growth models were associated with PC1 and descriptors derived directly from the data were associated with PC2. Based on principal component analysis, the structure of the IPCs varied with the crop, with AUIPCstd values of 28·18, 42·79 and 155·83 and Yf values of 53·58, 20·14 and 142·54 conidia m-3 h-1 in raspberry, strawberry and grape, respectively. Time to 50% of the maximum inoculum concentration was lower in raspberry and strawberry than in grape. The IPCs monitored in raspberry were characterized by narrow ranges for mean absolute rate (0·012-0·016) and AUIPCstd (16·80-48·85), the IPCs monitored in strawberry were characterized by wide ranges for mean absolute rate (0·031-0·080) and AUIPCstd (12·31-98·39), and the IPCs monitored in grape crops were characterized by a lower mean absolute rate (0·006-0·012) and a higher AUIPCstd (50·95-335·14). [ABSTRACT FROM AUTHOR]

Of 683 Botrytis cinerea isolates collected from a fungicidetrial vineyard, 31 were classified as putatively resistant to fenhexamid (50% effective concentration [EC50] ≥ 0.1 μg/ml). For the resistant isolates that survived and sporulated in culture, colony expansion and conidial germination frequency was significantly reduced relative to the mean of 30 representative baseline isolates (EC50 = 0.03 μg/ml). Grape berries were inoculated with four isolates representing a range of fenhexamid sensitivities and treated preventively or curatively with fenhexamid concentrations (150 to 600 mg/liter) representing 25 to 100% of the recommended rate. All treatments significantly delayed disease onset and progress caused by isolates with EC50 values of 0.03 and 0.15 μg/ml but provided little to no control of isolates with EC50 values of 0.32 and 62.5 μg/ml. The latter isolate exhibited a previously unreported F427V mutation of ERG27, an enzyme of ergosterol biosynthesis. In a duplex quantitative polymerase chain reaction test, the ratio of pathogen/host DNA increased significantly for 14 days after inoculation of untreated berries with a baseline isolate but declined slightly in berries treated with fenhexamid at 600 mg/liter 1 day post inoculation. In the vineyard, disease control was affected by the number and rate of fenhexamid applications but B. cinerea isolates with EC50 ≥ 0.1 μg/ml were not preferentially selected. [ABSTRACT FROM AUTHOR]

Many cryptic species have recently been discovered in fungi, especially in fungal plant pathogens. Cryptic fungal species co-occurring in sympatry may occupy slightly different ecological niches, for example infecting the same crop plant but specialized on different organs or having different phenologies. Identifying cryptic species in fungal pathogens of crops and determining their ecological specialization are therefore crucial for disease management. Here, we addressed this question in the ascomycete Botrytis cinerea, the agent of gray mold on a wide range of plants. On grape, B. cinerea causes severe damage but is also responsible for noble rot used for processing sweet wines. We used microsatellite genotyping and clustering methods to elucidate whether isolates sampled on gray mold versus noble rot symptoms in three French regions belong to genetically differentiated populations. The inferred population structure matched geography rather than the type of symptom. Noble rot symptoms therefore do not seem to be caused by a specific B. cinerea population but instead seem to depend essentially on microclimatic conditions, which has applied consequences for the production of sweet wines. [ABSTRACT FROM AUTHOR]

An instrument for the automatic quantification of glycerol in grapes has been developed. We verify here that this analyte can be used as a benchmark of a serious disease affecting the grapevines, namely Botrytis cinerea. The core of the instrument is an amperometric biosensor consisting of a disposable screen printed electrode, generating the analytical signal thanks to a bi-enzymatic process involving glycerol dehydrogenase and diaphorase. The full automation of the analysis is realised by three micropumps and a microprocessor under control of a personal computer. The pumps allow the correct and constant dilution of the grape juice with a buffer solution also containing [Fe(CN)6]3- redox mediator and the injection of NAD+ cofactor when the baseline signal reaches a steady state; the instrument leads to automated reading of the analytical signal and the consequent data treatment. Although the analytical method is based on an amperometric technique that, owing to heavy matrix effects, usually requires an internal calibration, the analyses indicate that a unique external calibration is suitable for giving accurate responses for any grapes, both white and black ones. [ABSTRACT FROM AUTHOR]

Background and aims: The fungus Botrytis cinerea is a common problem in viticulture and leads to serious losses in both yield and quality. The objective was to study the potential of the antagonist Pantoea ananatis BLBT1-08 for controlling this disease. Methods: Pathogen suppression by Pantoea treatments was investigated in different field trials and in detached leaf assays. The mode of action was studied by confocal laser scanning microscopy of treated grape leaves and by in vitro assays. Results: The introduction of P. ananatis BLBT1-08 in a 3-year field trial resulted in statistically significant reduction of disease symptoms. However, B. cinerea abundance, measured by quantitative real-time polymerase chain reaction of a B. cinerea specific gene, was not reduced when compared to non-treated, symptom-free leaves. A DsRed fluorescent protein labeled BLBT1-08 strain showed a high phyllosphere competence and competition on the leaf surface, but did not colonize the inner parts of plant tissue. Germination of B. cinerea was not inhibited by BLBT1-08 on the leaf, but mycelial growth and symptoms were suppressed without direct pathogen-antagonist contact. The antimicrobial activity was amino acid and temperature dependent. Conclusion: P. ananatis BLBT1-08 is a competitive and promising biocontrol agent for the control of B. cinerea and is highly effective at reducing disease incidence. [ABSTRACT FROM AUTHOR]

Molecular sequencing ( rpoB) and standard pathological and microbiological methods identified Pseudomonas syringae pv. syringae (Pss) as the causal agent of bacterial inflorescence rot of grapevines ( Vitis vinifera) in three vineyards in Tumbarumba, NSW, Australia in 2006 and 2007. Pss strains from shrivelled berries and necrotic inflorescences of diseased grapevines were used to inoculate leaves and inflorescences of potted cv. Semillon grapevines. Pss caused disease symptoms similar to those experienced in the field, including angular leaf lesions, longitudinal lesions in shoot tissues and rotting of inflorescences from before flowering until shortly after fruit set. High humidity promoted symptom severity. The necrotic bunch stem and leaf lesions were susceptible to the development of Botrytis cinerea infections. Cryo-scanning electron microscopy (cryoSEM) indicated that Pss entered leaves and inflorescence tissues via distorted, open, raised stomata surrounded by folds of tissue that appeared as 'star-shaped' callose-rich complexes when viewed by UV light microscopy. In necrotic tissues, cryoSEM revealed Pss within petiole parenchyma cells and air-filled rachis xylem vessels. This is the first report of inflorescence and hence fruit loss caused by Pss in grapevines. The disease is described as 'bacterial inflorescence rot' and regarded as one that expands the previously reported pathology of grapevines caused by P. syringae. This study also indicated that infection by Pss might promote destructive B. cinerea infections when the fungus is already present but latent, although further experimentation is needed to prove such an interaction. [ABSTRACT FROM AUTHOR]

Harvest bunch rot of wine grape, caused primarily by Botrytis cinerea, is a perennial problem limiting the productivity of eastern vineyards, especially on cultivars with compact clusters. The aim of the present study was to evatuate the effectiveness of gibberellic acid (GA) sprays at reducing the compactness of Chardonnay and Vignoles clusters and minimizing bunch rot. Applications of GA reduced the number of berries per centimeter and the incidence and severity of bunch rots in Vignoles and, to a lesser extent, in Chardonnay over three consecutive years; however, the magnitude of GA effects often depended on the timing and rate of application. Bloom GA applications were more effective (P < 0.001) at reducing compactness and bunch rots than prebloom applications. Significantly, negative effects of GA applications on yield were negligible based on data from 4 years of trials on single vines and 2 years of data on 24-vine plots of Vignoles, provided the rates did not exceed 25 ppm. Regression analysis showed that berries per centimeter accounted for between 89 and 94% of variation in the incidence of Botrytis rot on Vignoles. On Chardonnay, compactness accounted for 53% of the variation in incidence, and the estimated compactness level at which no bunch rot would occur was 4.40 ± I .05 (mean ± standard error) berries per centimeter. The relationship between cluster compactness and spray coverage of berries was also investigated in two separate experiments. Spray coverage of individual berries decreased linearly as cluster compactness increased within the range tested (3 to 18 berries per centimeter). Cluster compactness accounted for two-thirds of the variation in individual berry coverage, and coverage was reduced by 40 to 50% for clusters with about 1 8 berries per centimeter. These results strongly support the use of GA in integrated management of bunch rot on Vignoles and Chardonnay in eastern U.S. vineyards. [ABSTRACT FROM AUTHOR]

Viticulture in Michigan is limited by a cool and humid climate and as a result, there is a problem of harvest season cluster rot, especially in cultivars with compact cluster morphology. Economically important wine grape varieties in eastern North America possess varying susceptibility, to harvest season cluster rot. Some important cultivars that are susceptible are Pinot gris, Pinot noir, Riesling (Vitis vinifera L.) as well as Seyval and Vignoles (French-American hybrids or interspecific hybrid cultivars). A common characteristic of these cultivars is the compactness of the berries held on the cluster rachis. The aim of this work was to determine whether a quantified amount of leaf removal or a temporary reduction in carbon assimilation at the beginning of bloom would reduce fruit set and cluster compactness. Vines subjected to removal of four or six basal leaves had an average fruit set reduction of ≈45% from a non-treated control. Cluster weight and berries per cluster were similarly reduced with a greater effect on the basal than the apical cluster of the shoot. Reduced fruit set was associated with a reduction in cluster compactness and harvest season rot. This was also reflected in yield and basic fruit chemistry parameters associated with the importance of basal leaves to the developing cluster. Multiple applications of stylet oil at different time intervals resulted in significant reduction in net photosynthesis (Pn). A single application had no significant impact on Pn, whereas multiple applications reduced leaf assimilation rates. However, this reduction in Pn did not reduce fruit set or improve cluster compactness. There was a strong negative effect of early leaf removal in Year ! on vine performance in Year 2; this carryover effect increased shootless nodes per vine, reduced the number of clusters per shoot and per vine, and dramatically reduced fruit set and consequently yield per vine. [ABSTRACT FROM AUTHOR]

Botrytis cinerea (anamorph of Botryotinia fuckeliana) causes gray mold on a high number of crop plants including grapes. In this study, we investigated the genetic properties of a grape pathogenic population of B. cinerea in the area of Eger, Hungary. A total of 109 isolates from 12 areas were sampled. Based on the sequence of the β-tubulin (tub1) locus, they all belong to group II, a phylogenetic species within B. cinerea. Seventy-four isolates were classified as transposa, with both the Flipper and Boty transposons, and 10 were classified as vacuma, lacking both transposons. The remaining isolates contained either only Flipper (13) or Boty (12). Multilocus analysis of sequences from tub1 and two other loci (elongation factor 1-alpha, tef1, and a minisatellite from the intron of an ATPase, MSB1) led to poor phylogenetic resolution of strains in individual clades. Analysis of five microsatellites (Bc2, Bc3, Bc5, Bc6, and Bc10) resulted in 55 microsatellite haplotypes within the 109 strains. No correlation was detected among individual haplotypes and the presence/absence of Flipper and/or Boty, the geographic origin, or the year of isolation. Application of the index of association, the chi-square test, and the phi test consistently indicated that the population of Hungarian isolates of B. cinerea undergoes sexual reproduction. However, the index of association test suggested the presence of some clonality, and the fixation index showed a low or occasionally moderate level of fixation in the Flipper populations. We conclude that the B. cinerea populations in Hungary consist of a strongly recombining group II phylogenetic species. [ABSTRACT FROM AUTHOR]

The effectiveness of chitosan treatment of table grapes, alone or in combination with ultraviolet- C (UV-C) radiation, to control postharvest gray mold caused by Botrytis cinerea, was determined in California, United States. The influence of these treatments on catechin and resveratrol contents and chitinase activity in grape berry skins also was assessed. Clusters of cvs. Thompson Seedless, Autumn Black, and Emperor were sprayed in the vineyard with 1% chitosan, then harvested daily for 5 days. Promptly after harvest, they were inoculated with B. cinerea. Decay incidence and disease severity were significantly reduced by chitosan, which was most effective on berries harvested 1 or 2 days after treatment. In another experiment, grape berries were sprayed in the vineyard with chitosan, harvested 2 days later, irradiated for 5 mm with UV-C (0.36 J/cm²), and inoculated with B. cinerea 2 days later. Combined chitosan and UV-C treatments applied to cv. Autumn Black or selection B36-55 were synergistic in reducing gray mold incidence and severity compared with either treatment alone. Preharvest chitosan treatment increased neither concentration of catechin or resveratrol nor activity of chitinase in berry skin. Conversely, UV-C irradiation, alone or combined with chitosan treatment, induced catechin in cv. Autumn Black berries and trans-resveratrol in both cv. Autumn Black and selection B36-55. [ABSTRACT FROM AUTHOR]

There is increasing interest in the use of biological control agents (BCAs) and plant resistance stimulants to suppress botrytis bunch rot in grapes, caused by Botrytis cinerea. Numerous different filamentous fungi, bacteria and yeasts have been selected as potential BCAs for control of grey mould based upon demonstrated antagonism towards B. cinerea. Biological suppression of the pathogen arises via competition for nutrients and space, the production of inhibitory metabolites and/or parasitism. Preformed and inducible grapevine defence mechanisms also contribute to disease suppression by preventing or delaying pathogenic infection. Furthermore, various biotic and abiotic agents can stimulate grapevine defence mechanisms and so elevate resistance to B. cinerea infection. Biosuppression of B. cinerea in vineyards, using BCAs and resistance stimulants, has been inconsistent when compared with that observed in controlled glasshouse or laboratory conditions. This may be attributable, in part, to the innate variability of the field environment. Research to improve field efficacy has focused on formulation improvement, the use of BCA mixtures and combinational approaches involving BCAs and plant resistance stimulants with complementary modes of action. [ABSTRACT FROM AUTHOR]

The population structure of Botrytis cinerea was investigated by using transposable elements, DNA fingerprinting generated by microsatellite primed-polymerase chain reaction (MP-PCR), and sensitivity to the hydroxyanilide fungicide, fenhexamid, for 234 isolates collected from fig, grape, kiwifruit, pea, and squash in California. Among 234 isolates tested, 195 had two transposable elements, Bozy and Flipper (transposa type), 38 had only the Boty element (Boty type), and one had neither of these elements (vacuma type). Four of these 234 isolates, which belonged to hie Bosy type, were resistant to fenhexamid. A phenogram generated based on MP-PCR mark- ers showed that the isolates were not clustered based on their source hosts or the presence of transposable elements. Analysis of molecular variance (AMOVA) showed that there were no significant genetic differentiations among isolates collected from grape, kiwifruit, pea, and squash at the Kearney Agricultural Center. A more detailed analysis based on AMOVA partition of the total genetic variance indicated that 96% of the variation occurred within populations. The parsimony tree length permutation (PTLPT) and index of association (IA) analyses of MP-PCR data set were consistent with absence of sexual recombination in sampled populations of this pathogen. [ABSTRACT FROM AUTHOR]

The effect of volatiles from cv. Isabella (Vitis labrusca) on the growth of Botrytis cinerea was tested in vitro and in situ, in the latter case on 'Roditis' grapes (V vinifera), at various temperatures. The goal of the research was to determine whether the volatiles emitted by Isabella grapes could be effective biocontrol agents of Botrytis cinerea. The closed Mariotte system was used as a bioassay method to analyze quantitatively the biological action of these volatiles on fungal growth and disease development. The in vitro experiments revealed the inhibitory action of the Isabella volatiles on the sporulation and sclerotia formation of the fungus, as well as the stimulating action of the Roditis volatiles on the sporulation of the fungus. The in situ study confirmed the antifungal action of the Isabella volatiles as they reduced the inoculum and pathogenicity of B. cinerea. The antibiotic action was more pronounced at 21°C. The study indicates that Isabella volatiles act as biocontrol agents of B. cinerea. [ABSTRACT FROM AUTHOR]

Botrytis bunch rot caused by Botrytis cinerea is one of the most economically significant post-harvest diseases of grapes. In the present study, we showed that the bacterial strain Bvel1 is phylogenetically affiliated to Bacillus velezensis species. The strain Bvel1 and its secreted metabolites exerted an antifungal activity, under in vitro conditions, against B. cinerea. UHPLC–HRMS chemical analysis revealed that iturin A2, surfactin-C13 and -C15, oxydifficidin, bacillibactin, L-dihydroanticapsin, and azelaic acid were among the metabolites secreted by Bvel1. Treatment of wounded grape berries with Bacillus sp. Bvel1 cell culture was effective for controlling grey mold ingress and expansion in vivo. The effectiveness of this biological control agent was a function of the cell culture concentration of the antagonist applied, while preventive treatment proved to be more effective compared to curative. The strain Bvel1 exhibited an adequate colonization efficiency in wounded grapes. The whole-genome phylogeny, combined with ANI and dDDH analyses, provided compelling evidence that the strain Bvel1 should be taxonomically classified as Bacillus velezensis. Genome mining approaches showed that the strain Bvel1 harbors 13 antimicrobial biosynthetic gene clusters, including iturin A, fengycin, surfactin, bacilysin, difficidin, bacillaene, and bacillibactin. The results provide new insights into the understanding of the endophytic Bacillus velezensis Bvel1 biocontrol mechanism against post-harvest fungal pathogens, including bunch rot disease in grape berries. [ABSTRACT FROM AUTHOR]

Biocontrol is one of the most promising alternatives to synthetic fungicides for food preservation. Botrytis cinerea, Alternaria alternata, and Aspergillus section Nigri are the most concerning pathogens for grape development. However, frequently, other species, such as Penicillium glabrum in this study, are predominant in spoiled bunches. In this work, 54 native yeasts from vineyards were screened by direct confrontation in potato dextrose agar plates as antagonists against P. glabrum. Isolates of Pichia terricola, Aureobasidium pullulans, and Zygoascus meyerae were selected for their antagonist activity in vitro, plus isolates of Pichia kudriavzevii, Hormonema viticola, and Hanseniaspora uvarum were used as negative controls. However, in vivo, confrontations in wounded grapes showed disagreement with direct confrontation in vitro. P. terricola, P. kudriavzevii, H. viticola, Z. meyerae, and H. uvarum significantly reduced the incidence of P. glabrum on grapes. Nevertheless, P. terricola, H. viticola, and H. uvarum themselves spoiled the wounded grapes. Inhibitions were associated with different mechanisms such as the production of volatile organic compounds (VOCs), lytic enzymes, biofilm formation, and competition for nutrients. The isolates of P. kudriavzevii L18 (a producer of antifungal VOCs which completely inhibited the incidence of P. glabrum) and Z. meyerae L29 (with pectinase, chitinase and β-glucanase activity and biofilm formation which reduced 70% of the incidence of P. glabrum) are proposed as suitable biocontrol agents against P. glabrum. [ABSTRACT FROM AUTHOR]

Botrytis cinerea is the pathogen of gray mold disease affecting a wide range of plant hosts, with consequential economic losses worldwide. The increased frequency of fungicide resistance of the pathogen challenges its disease management, and thus the development of alternative control strategies are urgently required. In this study, we showed excellent synergistic interactions between resveratrol and pyrimethanil. Significant synergistic values were recorded by the two-drug combination on the suppression of mycelial growth and conidia germination of B. cinerea. The combination of resveratrol and pyrimethanil caused malformation of mycelia. Moreover, the inoculation assay was conducted on table grape and consistent synergistic suppression of the two-drug combination was found in vivo. Our findings first revealed that the combination of resveratrol and pyrimethanil has synergistic effects against resistant B. cinerea and support the potential use of resveratrol as a promising adjuvant on the control of gray mold. [ABSTRACT FROM AUTHOR]

Botrytis cinerea Pers. specie infects a large number of host plants in a variety of environmental conditions. Grey mould caused by Botrytis cinerea Pers. can cause dieback and decay of most plant parts, and a huge number of plant species can be affected including vegetables, soft fruits, ornamental plants and vine. The chemical control of plant diseases records a decrease and the biological control of plant diseases through herbal extracts gains more and more importance. Given the above mentioned facts and the fact that gray mold has a negative impact on the yield and quality of harvest this paper mainly aims at studying the control of gray mold by biological methods -hydroalcoholic extracts; the effect of different plant extracts on the emergence and development of mycelium [ABSTRACT FROM AUTHOR]

Presents an abstract of research entitled `Frequency of Dicarboximide and Benzimidazole Resistant Strains of Botrytis Cineria in Western Cape Table Grape Vineyards and Influence of Spray Schedules on Dicarboximide-Resistant Populations,' by P.H. Fourie and G. Holz.

Presents an abstract of the study `Monitoring resistance of Botrytis cinerea to dicarboximide fungicides on table grapes in the Western Cape,' by P.H. Fourie and G. Holz which was presented at the 33rd annual congress of the South African Society for Plant Pathology held from January 15-18, 1995 in South Africa.

An abstract of the article "Genomic and Proteomic Studies on the Pathogenic Grape Flora in Luxembourg" by M. Behr and colleagues is presented.