scholarly journals Epidemiological Model based Decision Support System for the Management of Grapes Downy Mildew

2020 ◽  
Vol 107 ◽  
pp. 1-4
Author(s):  
Sendhilvel v ◽  
◽  
Marimuthu T ◽  
Geetha Lakshmi V ◽  
◽  
...  
Keyword(s):  
Decision Support ◽  
Downy Mildew ◽  
Disease Incidence ◽  
Cost Effective ◽  
Plasmopara Viticola ◽  
Logistic Equation ◽  
Biological Data ◽  
Epidemiological Model ◽  
Progress Curve ◽  
Weather Parameters

Grapevine downy mildew caused by Plasmopara viticola is an explosivedisease that causes severe damage to leaf, flowers and fruits of the vine.In the present study, an epidemiological model was developed to supportthe vine-growers to reduce the number of fungicidal sprays and protect theenvironmental hazards besides saving the input cost. To record the weatherdata, an automatic weather station was installed at Mathampatti Village,Coimbatore, India and the weather parameters such as relative humidity,minimum, maximum and night temperatures, rainfall, leaf wetness, dew fall,solar radiation etc., were recorded at once in a 10 minutes interval during2014-17. A logistic equation was designed based on the biological data(disease incidence, weather parameter and crop age) and its mathematicalanalysis was shown in this paper. The critical weather parameters werestudied using logistic equation with the support of “Curve expert programme”.The mode described the development of the infection and infection ratethrough computation-based analysis. The Decision Support Systems (DSS)were arrived using the disease progress curve obtained from the logisticequation. The DSS indicates the first two sprays during the congenial phaseof the disease from 25 to 45 Days After Pruning (DAP). Then the secondphase, ie rapid growth stage was termed as ‘Exponential phase’, in which twosprays on 55 and 65 DAP (flowering and fruiting stage) were carried out. Inthe final plateau phase (66 DAP to till harvest), the management strategiesapplied would not be cost-effective and no spray was recommended. Thefield experiment was carried out using the findings of the logistic equationwith different management modules for validation. The number of spraysof fungicide was reduced from 15 to 5 times in the logistic equation-basedtreated plot.

scholarly journals Salvia officinalis Extract Can Protect Grapevine Against Plasmopara viticola

Plant Disease ◽  
2010 ◽  
Vol 94 (5) ◽  
pp. 575-580 ◽  
Author(s):  
Silvia Dagostin ◽  
Tiziano Formolo ◽  
Oscar Giovannini ◽  
Ilaria Pertot ◽  
Annegret Schmitt
Keyword(s):  
Disease Control ◽  
Downy Mildew ◽  
Disease Incidence ◽  
Plasmopara Viticola ◽  
Salvia Officinalis ◽  
Promising Alternative ◽  
Rainy Period ◽  
Grapevine Downy Mildew ◽  
Progress Curve ◽  
High Level

The ability of sage (Salvia officinalis) extract to control grapevine downy mildew under greenhouse and field conditions was tested. The persistence and rainfastness of sage extract were also investigated. Sage extract provided a high level of sustained disease control in artificially inoculated, potted grapevine under greenhouse conditions. However, even small amounts of simulated rainfall (10 mm) significantly reduced efficacy of sage extract. In a field experiment in 2006, sage extract provided 94% reduction in disease incidence and 63% reduction in area under the disease progress curve for disease severity on berries and leaves, respectively, reaching a level of disease control not significantly different from that provided by copper hydroxide. In 2007, the sage extract provided only a partial reduction (less than 30%) of downy mildew on leaves, probably as a result of a long rainy period between two of the consecutive treatments. Overall, sage extract effectively controlled grapevine downy mildew and could be a promising alternative to copper in organic viticulture. However, the low rainfastness of this treatment adversely affected its efficacy.

scholarly journals Evaluation of a Disease Warning System for Downy Mildew of Grapes

Plant Disease ◽  
2000 ◽  
Vol 84 (5) ◽  
pp. 549-554 ◽  
Author(s):  
L. V. Madden ◽  
M. A. Ellis ◽  
N. Lalancette ◽  
G. Hughes ◽  
L. L. Wilson
Keyword(s):  
Linear Model ◽  
Downy Mildew ◽  
Environmental Conditions ◽  
Generalized Linear Model ◽  
Disease Incidence ◽  
Warning System ◽  
Plasmopara Viticola ◽  
Effective Control ◽  
Subsequent Infection ◽  
Grape Downy Mildew

An electronic warning system for grape downy mildew— based on models for the infection of leaves of Vitis lambrusca, production of sporangia by Plasmopara viticola in lesions, and sporangial survival—was tested over 7 years in Ohio. Grapevines were sprayed with metalaxyl plus mancozeb (Ridomil MZ58) when the warning system indicated that environmental conditions were favorable for sporulation and subsequent infection. Over the 7 years, plots were sprayed from one to four times according to the warning system, and from four to 10 times according to the standard calendar-based schedule (depending on the date of the initiation of the experiment). The warning system resulted in yearly reductions of one to six sprays (with median of three sprays). Disease incidence (i.e., proportion of leaves with symptoms) in unsprayed plots at the end of the season ranged from 0 to 86%, with a median of 68%. Incidence generally was very similar for the warning-system and standard-schedule treatments (median of 7% of the leaves with symptoms), and both of these incidence values were significantly lower (P < 0.05) than that found for the unsprayed control, based on a generalized-linear-model analysis. Simplifications of the disease warning system, where sprays were applied based only on the infection or sporulation components of the system, were also effective in controlling the disease, although more fungicide applications sometimes were applied. Effective control of downy mildew, therefore, can be achieved with the use of the warning system with fewer sprays than a with a standard schedule.

scholarly journals Components of Quantitative Resistance to Philippine Downy Mildew In Maize

Zuriat ◽  
2015 ◽  
Vol 13 (1) ◽  
Author(s):  
D. Ruswandi ◽  
A. D. Raymundo ◽  
R. M. Lantican ◽  
D. M. Hautea ◽  
A. M. Salazar ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Inbred Line ◽  
Host Resistance ◽  
Quantitative Resistance ◽  
Disease Incidence ◽  
Transgressive Segregation ◽  
Adult Plant ◽  
Progress Curve ◽  
Systemic Symptoms ◽  
Line P

Resistance to Philippine downy mildew (Peronosclerospora philippinensis) was observed in a BC1F2 population developed from a cross between the susceptible inbred line Pi 23 and the resistant inbred line P 345. Five components of resistance namely, disease incidence, disease severity, onset of systemic symptoms, the-area- underdisease-progress- curve (AUDPC), and rate of downy mildew development affected host resistance reactions. All components were significantly correlated. The adult plant resistant reaction was evident in resistant progenies showing prolonged onset of systemic symptoms. Transgressive segregation that exceeded the high and low parent values was also observed for all components of quantitative resistance to Philippine downy mildew.

scholarly journals IMPROVED DOWNY MILDEW CONTROL IN WINE GRAPES WITH VOSSEN BLUE

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 605d-605
Author(s):  
Joseph A. Fiola ◽  
Gary C. Pavlis
Keyword(s):  
Downy Mildew ◽  
Disease Incidence ◽  
Total Yield ◽  
Economic Loss ◽  
Plasmopara Viticola ◽  
Wine Grapes ◽  
Incidence Data ◽  
Average Cluster ◽  
Grape Cultivars ◽  
Downy Mildew Disease

Downy Mildew, Plasmopara viticola, causes major damage and economic loss to many wine grape cultivars grown in the Northeast. The purpose of the experiment was to test the efficacy of Vossen Blue (VB; iron pigment) in association with fungicides for the control of Downy Mildew disease of wine grapes in New Jersey. The experimental plot was a planting of `Seyval Blanc' (5th leaf). Treatments (applied via back-pack sprayer) included no fungicide (control I), full fungicide (FF) (RCE commercial recs; control II), FF + 4%VB, FF + 8%VB, 8%VB, Half Rate Fungicide (HF) + 4%VB, HF + 8%VB. There were no significant differences between treatments for total yield, average cluster weight, average berry weight, Brix %, and pH. Spectrophotometric (Hunter's Lab) analysis of foliage samples revealed that leaf samples from the VB treatments had greater green color (correlate: increased chlorophyll). Analysis of subjective (1-9) disease incidence data: FF8 significantly lower disease score that FF; FF4, HF4, HF8, and FF no difference. Compared to normal full fungicide: superior Downy Mildew control was achieved by adding VB to full fungicide; equal control was achieved with half fungicide and VB.

scholarly journals Evaluation of wheat genotypes resistance to Fusarium head blight in Paraguay

2020 ◽  
Vol 50 ◽  
Author(s):  
Cinthia Carolina Cazal-Martínez ◽  
Yessica Magaliz Reyes-Caballero ◽  
Pastor Enmanuel Pérez-Estigarribia ◽  
Andrea Alejandra Arrúa-Alvarenga ◽  
Juliana Moura Mendes ◽  
...  
Keyword(s):  
Grain Yield ◽  
Fusarium Head Blight ◽  
Disease Incidence ◽  
Genetic Resistance ◽  
Cost Effective ◽  
Yield Potential ◽  
Head Blight ◽  
Resistance Level ◽  
Wheat Genotypes ◽  
Progress Curve

ABSTRACT Fusarium head blight (FHB), or scab, caused by a Fusarium spp. complex, is an important wheat disease in Paraguay. Among the strategies used to control it, the genetic resistance is considered highly efficient and cost effective. This study aimed to evaluate and compare the effects of F. graminearum on six wheat genotypes, including two comparison varieties, in two seeding dates. The genotypes were artificially inoculated in the spike, at the flowering stage, by injecting a pool of four pathogenic F. graminearum isolates. The FHB development was evaluated by scoring the disease incidence and severity, percentage of diseased spikelets and damaged kernels, as well as using the area under the disease progress curve. Besides the kernel infection, its impact on the development of mycotoxins (deoxynivalenol) and interactions with the genotypes were also evaluated. The results identified an advanced breeding line (Lin 84) with a resistance level to FHB comparable to that of the universally known resistance sources (Sumai 3 and Frontana). The other three genotypes (Caninde 11, Caninde 12 and Caninde 21), in spite of presenting a higher grain yield potential, were evaluated as moderately susceptible to susceptible. These results suggest that, although it is possible to transfer the FHB resistance to a higher agronomic type, combining such resistance with a higher grain yield potential remains an ongoing challenge.

scholarly journals Rpv Mediated Defense Responses in Grapevine Offspring Resistant to Plasmopara viticola

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 781
Author(s):  
Tyrone Possamai ◽  
Daniele Migliaro ◽  
Massimo Gardiman ◽  
Riccardo Velasco ◽  
Barbara De Nardi
Keyword(s):  
Downy Mildew ◽  
Cost Effective ◽  
Plasmopara Viticola ◽  
Defense Responses ◽  
Resistance Level ◽  
Resistance Response ◽  
Host Pathogen Interaction ◽  
Resistant Varieties ◽  
New Varieties ◽  
Independent Features

Downy mildew, caused by the biotrophic oomycete Plasmopara viticola, is one of the most serious grapevine diseases. The development of new varieties, showing partial resistance to downy mildew, through traditional breeding provides a sustainable and effective solution for disease management. Marker-assisted-selection (MAS) provide fast and cost-effective genotyping methods, but phenotyping remains necessary to characterize the host–pathogen interaction and assess the effective resistance level of new varieties as well as to validate MAS selection. In this study, the Rpv mediated defense responses were investigated in 31 genotypes, encompassing susceptible and resistant varieties and 26 seedlings, following inoculation of leaf discs with P. viticola. The offspring differed in Rpv loci inherited (none, one or two): Rpv3-3 and Rpv10 from Solaris and Rpv3-1 and Rpv12 from Kozma 20-3. To improve the assessment of different resistance responses, pathogen reaction (sporulation) and host reaction (necrosis) were scored separately as independent features. They were differently expressed depending on Rpv locus: offspring carrying Rpv3-1 and Rpv12 loci showed the strongest resistance response (scarce sporulation and necrosis), those carrying Rpv3-3 locus showed the highest levels of necrosis while Rpv10 carrying genotypes showed intermediate levels of both sporulation and necrosis.

scholarly journals Plasmopara viticola causing downy mildew on Vitis davidii in Korea

Plant Disease ◽  
2021 ◽  
Author(s):  
Bora Kim ◽  
Jae Sung Lee ◽  
Young-Joon Choi
Keyword(s):  
Downy Mildew ◽  
Disease Incidence ◽  
Plasmopara Viticola ◽  
Central China ◽  
Representative Specimen ◽  
Pathogenicity Test ◽  
Beta Tubulin ◽  
Vitis Species ◽  
Molecular Features ◽  
Vitis Davidii

Vitis davidii (Rom.Caill.) Foëx, commonly known as spine grape, is a deciduous climber native to China. Its fruits are consumed fresh or used to make wine in South and Central China. In recent years, spine grape has been cultivated in Korea. In July 2020, downy mildew was detected on spine grape vines in Jeongeup (35°42′17″N, 126°54′02″E), Korea, with a disease incidence of 70%. The symptoms appeared as yellowish, brownish, or reddish, vein-limited, poly-angular adaxial leaf spots, correspond to dense, white downy growth abaxially. A representative specimen was deposited in the Kunsan National University Herbarium (KSNUH679). Sporangiophores were tree-like, hyaline, mostly straight, and monopodially branched in orders of three to six; they measured (219.4–)273.2 to 435.1(–546.6) × (4.8–)6.7 to 9.0(–10.0) μm (n = 50). Ultimate branchlets were bi or trifurcate, straight to slightly curved, with truncate or, rarely, a swollen tip and measured 2.9 to 9.7 μm long and 0.8 to 2.5 μm wide at the base (n = 50). Sporangia were hyaline, ovoidal or lemon-shaped; they measured (16.8–)20.0 to 28.8(–34.2) × (11.4–)13.1 to 17.0(–20.1) μm with a length to width ratio of (1.28–)1.46 to 1.78(–2.07) (n = 50). This morphology was as described for Plasmopara viticola (Berk. & M. A. Curtis) Berl. & De Toni (Hall, 1989). Genomic DNA was extracted directly from infected V. davidii leaves. Three regions were PCR-amplified and sequenced: cox2 mtDNA with primers cox2F and cox2-RC4 (Choi et al., 2015), actin with primers pve04815-F and pve04815-R, and beta-tubulin with primers pvc389-F3 and pvc389-R4 (Rouxel et al., 2013). The resulting sequences were deposited in GenBank (accession nos. MT834527 for cox2, MT834525 for actin, and MT834526 for beta-tubulin). A BLASTn search revealed that the Korean sample was identical to P. viticola clade aestivalis originating from Vitis species: MK215072 for cox2 sequence, KY933800 for actin, and MK358393 for beta-tubulin. In all phylogenetic analyses of the three genes (cox2, actin, and beta-tubulin), KSNUH679 came out as phylogenetically place within P. viticola clade aestivalis, which has recently been reported on V. coignetiae and V. ficifolia var. sinuata in Korea (Kim et al., 2019). A pathogenicity test was performed twice by inoculating the leaves of 10 healthy spine grape plants with a sporangial suspension (~1 × 106 sporangia·mL-1) and incubating them in a growth chamber at 25 °C, 12-h day/night cycle, and 90% relative humidity; five non-inoculated plants served as controls. After two weeks, all inoculated plants developed typical downy mildew symptoms could be observed, whereas the controls remained symptomless. Morphology and molecular features confirmed the identity of the pathogen of spine grape to be P. viticola. To the best of our knowledge, this is the first report of downy mildew caused by P. viticola on V. davidii in Korea. Recently, downy mildew outbreaks caused by P. viticola have been recorded in spine grape plantations in southern China (Yi et al., 2019). Considering the potential of spine grape as a novel crop for Korea, P. viticola appears to represent a significant threat to this industry.

scholarly journals Evaluation of foliar resistance of grapevine genetic resources to downy mildew (Plasmopara viticola)

2012 ◽  
Vol 60 (8) ◽  
pp. 191-198 ◽  
Author(s):  
Pavel Pavloušek
Keyword(s):  
Downy Mildew ◽  
Disease Incidence ◽  
Natural Infection ◽  
Plasmopara Viticola ◽  
Methods Of Evaluation ◽  
Infection Pressure ◽  
Foliar Resistance ◽  
Term Evaluation ◽  
Term Field

In this study altogether the resistance of 44 grapevine cultivars to downy mildew was evaluated in a long-term field experiment (1996–2003). The resistance was evaluated under conditions of a natural infection pressure using the OIV 452 scale as well as on the base of the evaluation of disease incidence of sporulation and disease incidence of necrosis. The highest degree of resistance to downy mildew was found out in resistance donors Seyve Villard 12 375, Seibel 13 666 and Bianca cultivar. High correlations existing among individual methods of evaluation indicated a good applicability of all tested methods. The evaluation of disease incidence of sporulation and disease incidence of necrosis demonstrated the dependence of traits associated with the resistance to downy mildew on the colour of berries. When evaluating the correlation existing between the resistance and pedigree, it was demonstrated that the highest average resistance existed in cultivars that had the cultivar Seyve Villard 12 375 as the donor of resistance in their pedigree. Basing on obtained results it can be concluded that the OIV 452 scale can be considered as the basic method of resistance evaluation to downy mildew, above all in cases of a long-term evaluation under field conditions.

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