Mildew Of Grape Research Articles

New Strain of Bacillus amyloliquefaciens G1 as a Potential Downy Mildew Biocontrol Agent for Grape

To obtain effective biocontrol strains for downy mildew of grape, 38 endophytic bacteria were isolated from fruits, seeds, and old stems of six grape varieties. Using spot inoculation mixtures of sporangial suspensions of Plasmopara viticola and biocontrol bacterial suspension, this screen yielded three strains (G1, G5, and G9) with good antagonistic effects against P. viticola. The growth inhibition rate was 100%, which was comparable to the effect of the positive control Bacillus subtilis strain CN181. The enzyme activity and the metabolites of strain G1 were examined on casein hydrolysate medium, sodium carboxymethyl cellulose agar plates, and chrome azurol sulfonate (CAS) agar plates. The antifungal protein component was identified by liquid chromatography–mass spectrometry (LC–MS). The results showed that strain G1 was more effective against Plasmopara viticola after two field trials, and the inhibition rates of strain G1 on the seventh day of the two field trials were 47.5% and 36.9%, respectively. Strain G1 was identified as Bacillus amyloliquefaciens based on morphological examination and 16S rDNA sequence analysis. It produced proteases, cellulases, and siderophores. Crude protein of the strain mainly included the putative segregation protein SpoVG, which inhibited P. viticola.

Bioefficacy Studies of <i>Trichoderma asperelloides</i> and <i>Ampelomyces quisqualis</i> in Combination with Sulphur for the Management of Powdery Mildew of Grapes

A field experiment was carried out to evaluate the bio-efficacy of Trichoderma asperelloides and Ampelomyces quisqualis against powdery mildew of grapes at ICAR- National Research Centre for Grapes, Pune in 2021-22 and 2022-23. It was observed, that spray and drench of Trichoderma asperelloides @ 2 mlL-1 along with drench of Ampelomyces quisqualis @ 5 mlL-1 and spray of Sulphur @ 2gL-1 of water manifested the lowest percent disease index on leaves and bunches with PDI 21.84 and 19.21 respectively. The percent disease control on leaves and bunches was 54.64 and 59.04 respectively. Moreover, the application of Trichoderma asperelloides and Ampelomyces quisqualis solo and in combination with sulfur showed a significant impact on qualitative parameters such as pH, total soluble solids, acidity, berry diameter, berry length and shelf life. Hence this treatment may be recommended for the management of powdery mildew of grapes.

Identification of he-ne laser based mutation induced bacteria against grape disease

In the present study six bacterial strains from the soil of grape orchard were isolated and identified. Their antagonistic ability against Uncinula necator and Plasmopara viticola which cause downy mildew and powdery mildew of grapes, respectively were studied. Through phenotypic, physiological and biochemical studies, SF6 strain was identified as Bacillus subtilis which can effectively inhibit the growth of Uncinula necator and Plasmopara viticola of grapes. In order to enhance the antagonistic ability of the SF6 strain, mutation was induced by He-Ne laser radiation and, six mutant strains were obtained. Among the six mutant strains, SF66 showed the strongest antagonistic activity to Uncinula necator and Plasmopara viticola of grapes with its genetic stability. The finding of this research provides important impetus for the development of beneficial antagonistic microorganisms through He-Ne laser radiation breeding. Bangladesh J. Bot. 53(1): 33-40, 2024 (March)

Evaluation of an integrated control program for Downy mildew of grapes in Egypt

Evaluation of an integrated control program for Downy mildew of grapes in Egypt

The Vitis yeshanensis U-box E3 ubiquitin ligase VyPUB21 enhances resistance to powdery mildew by targeting degradation of NIM1-interacting (NIMIN) protein.

VyPUB21 plays a key role during the defense against powdery mildew in grapes. Ubiquitin-ligating enzyme (E3), a type of protein widely found in plants, plays a key role in their resistance to disease. Yet how E3 participates in the disease-resistant response of Chinese wild grapevine (Vitis yeshanensis) remains unclear. Here we isolated and identified a U-box type E3 ubiquitin ligase, VyPUB21, from V. yeshanensis. This gene's expression level rose rapidly after induction by exogenous salicylic acid (SA), jasmonic acid (JA), and ethylene (ETH) and powdery mildew. In vitro ubiquitination assay results revealed VyPUB21 could produce ubiquitination bands after co-incubation with ubiquitin, ubiquitin-activating enzyme (E1), and ubiquitin-conjugating enzyme (E2); further, mutation of the conserved amino acid site in the U-box can inhibit the ubiquitination. Transgenic VyPUB21 Arabidopsis had low susceptibility to powdery mildew, and significantly fewer conidiophores and spores on its leaves. Expression levels of disease resistance-related genes were also augmented in transgenic Arabidopsis, and its SA concentration also significantly increased. VyPUB21 interacts with VyNIMIN and targets VyNIMIN protein hydrolysis through the 26S proteasome system. Thus, the repressive effect of the NIMIN-NPR complex on the late systemic acquired resistance (SAR) gene was attenuated, resulting in enhanced resistance to powdery mildew. These results indicate that VyPUB21 encoding ubiquitin ligase U-box E3 activates the SA signaling pathway, and VyPUB21 promotes the expression of late SAR gene by degrading the important protein VyNIMIN of SA signaling pathway, thus enhancing grape resistance to powdery mildew.

Traditional and Emerging Approaches for Disease Management of Plasmopara viticola, Causal Agent of Downy Mildew of Grape

The oomycete Plasmopara viticola, which causes downy mildew, is currently one of the most destructive pathogens affecting grape production. Although native to the eastern United States, P. viticola was introduced into Europe in the mid-to-late 1800s and is now found in virtually every grape-growing region of the world. Since its discovery, much effort has been made to understand the life cycle and infection process of the pathogen to develop more effective management practices. Widespread application of fungicides, especially those which have only one mode of action, has led to an increased occurrence of resistance to these treatments. Thus, with increased fungicide resistance and rising environmental concerns surrounding their use, traditional chemical management practices have begun to fall out of favor. Newer approaches, from targeted breeding utilizing quantitative trait loci to biological control agents, are continually being investigated and adapted to limit the damage caused by downy mildew. This review summarizes the current knowledge of the pathogen and methods of its control and explores potential avenues for future research focused on hypovirulence and biological control agents.

Field appraisal of Picarbutrazox 9.53 % w/w (100 SC) against downy mildew of grapes

Field appraisal of Picarbutrazox 9.53 % w/w (100 SC) against downy mildew of grapes

Effect of weather parameters on the growth and development of downy mildew of grape caused by Plasmopara viticola

Effect of weather parameters on the growth and development of downy mildew of grape caused by Plasmopara viticola

Antimicrobial nature of specific compounds of Ampelomyces quisqualis identified from gas chromatography-mass spectrometry (GCMS) analysis and their mycoparasite nature against powdery mildew of grapes

Grapevine powdery mildew is the world's most important plant disease, and Ampelomyces frequently fight them. While it does not usually cause plant death, its major infections can result in significant production losses and severely impact wine quality. Fungicides are frequently used to control the disease, which can have long-term adverse effects on the ecosystem. As a result, alternative and environmentally friendly disease management approaches must be developed. The study aimed to reduce costly and toxic fungicide use by using Ampelomyces, a natural biofungicide, against various powdery mildew fungi. GC-MS analysis was also used to determine the antagonistic potential and efficacy of volatile organic chemicals produced by several Ampelomyces spp. against Erysiphe necator, which causes powdery mildew of grapes. The molecular characterization of A. quisqualis isolates based on using rDNA ITS region was also carried out and sequenced. GC-MS analysis identified various antimicrobial compounds, such as squalene (4.643%), octadecanoic acid (3.862%), tetradecanoic acid (3.600%), and 9,12-octadecadienoic acid (Z,Z) (1.451%). The least abundant compounds were 2-Hexadecanol, 1-Tricosanol, and 2-propenyl ester, with percentages of 0.485, 0.519, and 0.560, respectively. These bioactive compounds revealed by GC-MS analysis in crude extracts of A. quisqualis had a stronger antifungal and antibacterial activity against E. necator. As a result, using A. quisqualis to control the powdery mildew of grapes significantly reduced pathogen growth and disease incidence.

Exploring eco-sensitive strategies for effective powdery mildew management in grapevines

Grapevine powdery mildew is one of the most important plant diseases widely affecting crops in many countries. The main aim of the present study was to use Ampelomyces quisqualis isolates to suppress the powdery mildew of grapes under field conditions. The findings revealed a strong correlation between the mycoparasite, Ampelomyces quisqualis and the grape powdery mildew pathogens, suggesting its potential for effective control. The results revealed that a single spray of A. quisqualis @ 2.0 per cent (MDU1) succeeded by two sprays of Trichoderma asperellum @ 2.0 per cent (Tasp,7) were found to be effective against Erysiphe necator. In addition, liquid formulation of A. quisqualis isolate MDU1 (2% w/v) as a foliar spray at 2% containing 2 × 106 spores ml-1 the during initial occurrence of the disease up to three sprayings at 15 days interval was found to be best. Thus, a liquid formulation of A. quisqualis isolate MDU1 proved effective in managing grapes powdery mildew disease under field conditions. The rDNA ITS region of A. quisqualis isolates was analyzed at the molecular level, and the resulting sequences were subjected to GC-MS analysis. The secondary metabolite identification using GC-MS revealed the presence of antimicrobial compounds, including squalene with the highest peak of 4.643 percent, octadecanoic acid with 3.862 percent, tetradecanoic acid with 3.600 percent, and 9,12-octadecadienoic acid (Z,Z) with 1.451 percent. These bioactive compounds revealed by GC-MS analysis in crude extracts of A. quisqualis had a stronger antifungal activity against E. necator.

Genome Resource of Streptomyces atratus PY-1, a Broad-Spectrum Antimicrobial Strain in Particular Antagonistic Against Plasmopara viticola.

Streptomyces atratus PY-1 exhibited promising antimicrobial properties; in particular, it is highly inhibitory to Plasmopara viticola, which causes downy mildew of grape. It is very necessary to carry out systematic and in-depth research on the PY-1 strain for the improvement, application, and promotion of biocontrol agents. The PY-1 genome was fully sequenced and assembled. We present the draft genome sequence of PY-1, with a size of 9, 254, and 781 bp. Preliminary analysis on the PY-1 genome sequence shows that at least 35 gene clusters are involved in the biosynthesis of polyketides, terpenes, and nonribosomally synthesized peptides.

Strategic Management of Powdery Mildew of Grapes Using Fungicides and Bio-Control Agents

The study was carried out at ICAR-NRCG, Pune, Maharashtra, India during November–February of 2019–2020 and 2020–2021 to evaluate the bio-efficacy of fungicides and biocontrol agents and level of tolerance against powdery mildew of grapes. Total 18 treatments categorised into three groups were taken into account. Three groups viz. fungicides, biocontrol agents (Bacillus licheniformis, Trichoderma afroharzianum, Ampelomyces quisqualis) along with metrafenone and commercial formulations of biocontrol agents were analysed for disease control. A total of five applications of each treatment were made during the growing season. Results showed that, in case of Group I (registered fungicides), Hexaconazole 5 EC @ 1 ml l-1/ Difenoconazole 25 EC @ 0.5 ml l-1/Myclobutanil 10 WP @ 0.4 g l-1/Two sprays of sulphur @ 2 g l-1 was most effective in controlling the disease. In case of pure culture, Trichoderma afroharzanium had proved to be most effective in the control of powdery mildew when sprayed in alteration with Metrafenone. In Group III, alternate applications of commercial formulations of Bacillus subtilis (2 ml l-1), Trichoderma viridae (2 g l-1), Ampelomyces quisqualis (5 ml l-1) and sulphur (2 g l-1) was most effective in controlling the disease. It was concluded that the application of bio-control agents in alternation with chemical fungicides controlled the disease effectively.

Effect of different temperatures, relative humidity, incubation period on conidialgermination of Erysiphe necator causing powdery mildew of grapes

In vitro studies were conducted to assess the effect of different temperatures, relative humidity and incubationperiod on conidial germination of Erysiphe necator (powdery mildew) at the Department of Plant Pathology, College ofAgriculture, Vijayapur during 2020-22. Physiological studies of E. necator revealed that incubation of powdery mildewfungal spore suspension at various intervals indicated fairly satisfactory conidial germination from 18 to 22 hrs andultimately reached maximum at 24 hrs after incubation in distilled water. Among the different relative humidity (RH) levelsused for conidial germination, maximum germination was observed at 80 per cent RH (82.67%). howver, relative humidityranging from 80 to 85 per cent was found suitable for conidial germination of E. necator. Maximum conidial germination(83.69%) of E. necator was observed at 25 °C after 24 hrs and optimum temperature range for the conidial germination was20-25 °C.

MANAGEMENT OF DOWNY MILDEW OF GRAPES BY NEW COMBINATION FUNGICIDE OXATHIAPIPROLIN 0.6% + MANCOZEB 60% WG IN INDIA

Downy mildew of grapes caused by Plasmopara viticola is the most important disease of grapes which is observed in all grape growing regions of India. A new fungicide Oxathiapiprolin (piperidinylthiazoleisoxazoline class) along with Mancozeb (ethylene-bis-dithiocarbamate) was evaluated against downy mildew of grapes in the year 2018-19 and 2019-20 under field conditions at Maharashtra. Three concentrations of Oxathiapiprolin 0.6% + Mancozeb 60% WG, i.e. 1666, 2500 and 3333 g/ha were checked in the experiment. Pooled data revealed that the test fungicide@ 3333 g/ha manifested lowest PDI of 11.25 with a corresponding yield of 22.99 t/ha and it was at par with @2500 g/ha which had a PDI of 12.13 and yield of 22.31 t/ha. Hence the treatment Oxathiapiprolin 0.6% + Mancozeb 60% WG @ 3333 g/ha may be recommended against downy mildew of grapes.

Performance and Phytotoxicity assessment of Mancozeb 40% + Azoxystrobin 7% OS against downy mildew of grapes in Maharashtra, India

Performance and Phytotoxicity assessment of Mancozeb 40% + Azoxystrobin 7% OS against downy mildew of grapes in Maharashtra, India

A Comparative Analysis of Microbe-Based Technologies Developed at ICAR-NBAIM Against Erysiphe necator Causing Powdery Mildew Disease in Grapes (Vitis vinifera L.).

Globally, Erysiphe necator causing powdery mildew disease in grapevines (Vitis vinifera L.) is the second most important endemic disease, causing huge economic losses every year. At present, the management of powdery mildew in grapes is largely dependent upon the use of chemical fungicides. Grapes are being considered as one of the high pesticide-demanding crops. Looking at the residual impact of toxic chemical pesticides on the environment, animal, and human health, microbe-based strategies for control of powdery mildew is an emerging technique. It offers an environment-friendly, residue-free, and effective yet safer approach to control powdery mildew disease in grapes. The mode of action is relatively diverse as well as specific to different pathosystems. Hence, the aim of this study was to evaluate the microbe-based technologies, i.e., Eco-pesticide®, Bio-Pulse®, and Bio-Care 24® developed at the Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-NBAIM, Kushmaur, against grape powdery mildew and to integrate these technologies with a safer fungicide (sulfur) to achieve better disease control under organic systems of viticulture. The experiments were conducted at four different locations, namely, the vineyards of ICAR-NRCG, Rajya Draksha Bagayatdar Sangh (MRDBS), and two farmers' fields at Narayangaon and Junnar in the Pune district of Maharashtra. A significantly lower percent disease index (PDI) was recorded on the leaves of grape plants treated with Eco-Pesticide®/sulfur (22.37) followed by Bio-Pulse®/sulfur (22.62) and Bio-Care 24®/sulfur (24.62) at NRCG. A similar trend was observed with the lowest PDI on bunches of Eco-pesticide®/sulfur-treated plants (24.71) followed by Bio-Pulse®/sulfur (24.94) and Bio-Care®/sulfur (26.77). The application of microbial inoculants singly or in combination with sulfur has a significant positive impact on the qualitative parameters such as pH, total soluble solids (TSS), acidity, berry diameter, and berry length of the grapes at different locations. Among all the treatments, the Bio-Pulse®/sulfur treatment showed the highest yield per vine (15.02 kg), which was on par with the treatment Eco-Pesticide®/sulfur (14.94). When compared with the yield obtained from the untreated control, 2.5 to 3 times more yield was recorded in the plants treated with either of the biopesticides used in combination with sulfur. Even in the case of individual inoculation, the yield per vine was approximately two times higher than the untreated control and water-treated plants across the test locations. Results suggested that microbial technologies not only protect grapevines from powdery mildew but also enhance the quality parameters with increased yield across the test locations.

Identification of long non-coding RNAs in response to downy mildew stress in grape

The importance of long non-coding RNA in plant has been reported more and more in recent years, but there has been few specific reports on lncRNAs in grape, especially in terms of disease resistance. We performed RNA-seq on grape leaves of two species (<italic>Vitis piasezkii</italic> accession Liuba-8, <italic>Vitis vinifera</italic> cultivar Pinot Noir) sampled at six time points after inoculation, and 4011 possible lncRNAs were identified. The characteristics of grape lncRNAs were analyzed, and it was found that lncRNAs showed relatively consistent characteristics with the reported lncRNAs in model plants. 3,643 lncRNAs were predicted that have cis-regulatory effects on 6,622 protein-coding genes and 91 DElncRNAs were revealed to be coexpressed with its trans-regulated coding genes. 117 grape microRNAs were predicted to potentially target 184 lncRNAs and 6 lncRNAs were predicted to be endogenous targeting mimics of 15 microRNAs, among which some miRNAs have been reported in grape disease resistance. At six time points, LncRNAs showed different expression levels and different expression patterns in two species, suggesting that lncRNAs may have a certain regulatory effect on resistance to downy mildew in grape. Finally, a lncRNA MSTRG.12742.1 which may play a positive role in grape downy mildew resistance was verified by transient transformation. Its potential target gene, VIT_204s0008g02671.1, encodes cryptochrome DASH which may regulate stomatal opening and closing of plant leaves. In this study, we provided the systematic identification of lncRNAs in the course of downy mildew of grape, laying a foundation for further studies on downy mildew and lncRNAs of grape in the future.

Myclobutanil 10 wp, a fungicide to control powdery mildew of grape in cold arid zone of Kargil, Ladakh

Myclobutanil 10 wp, a fungicide to control powdery mildew of grape in cold arid zone of Kargil, Ladakh

Characterization of Powdery Mildew Pathogen (Erysiphenecator) [Schw.Burr] Infecting Grapes in Tamil Nadu

Powdery mildew of grapes is one of the most criticalwidespread and destructive diseases worldwide, and it causes yield reduction upto 65-80 percent. In the present study, the survey was conducted in different districts of Tamil Nadu and percent disease index wasassessed. The preliminary identification of the pathogen was madethrough phase contrast microscopic observation such as color, shape,and size of the conidia were measured as well as scanning electron microscopy was also used to study the morphometric characters of E.necator. Further,the isolates were confirmed through PCR analysis which yielded an amplicon size of 470 bp while using the specific primers (cyt b forward and cyt b reverse) targeting the E.necator

The use of a microbiological preparation based on Bacillus subtilis in organic viticulture

In organic farming, microbiological preparations are an alternative to chemical pesticides and mineral fertilizers. The article summarizes the experience of a three-year use of the biofungicide Extrasol in combination with colloidal sulfur in the vineyards of the Crimea. The use of the biofungicides makes it possible to control the development of powdery mildew of grape at the level of chemical plant protection products, including during the years of epiphytoties: on the cv. Bastardo magarachskiy grapes – 7.1–14.7 %, on the Italy grape cultivar – up to 5.2%. The degree of influence of the biofungicide Extrasol on the phenolic and oxidase complex of grapes depends on the background level of development of Uncinula necator and the biological effectiveness of the treatment. In comparison with chemical means of protection, the smallest effect of processing cv. Bastardo magarachskiy grapes with a biological product in relation to the accumulation of phenolic compounds was observed at a level of powdery mildew development of 30-50 %; the maximum increase in the technological reserve of phenolic compounds was 59 %, anthocyanins – 12 %; the activity of polyphenol oxidase increased 1.1–3.3 times. The use of the biofungicide Extrasol on Italian grape cultivar led to an increase in the weight of the bunch by an average of 11 %, yield – by 25.6 %, titratable acids – by 9.6 % relative to chemicals; improved the aroma, taste and texture of the berry.