scholarly journals Modelling the effect of partial resistance on epidemics of downy mildew of grapevine

2021 ◽  
Author(s):  
Federica Bove ◽  
Serge Savary ◽  
Laetitia Willocquet ◽  
Vittorio Rossi
Keyword(s):  
Downy Mildew ◽  
Partial Resistance ◽  
Latency Period ◽  
Suppressive Effect ◽  
Disease Suppression ◽  
Infectious Period ◽  
Relative Resistance ◽  
Disease Progress ◽  
Progress Curve ◽  
The Impact

AbstractThe cultivation of grape varieties with partial resistance to disease may become an important component for disease management in the future. The impact of partial resistance on downy mildew epidemics according to its components have not been explored so far. This work aims to model, understand, and quantitatively analyse the effect of partial resistance against dual disease epidemics (foliage and clusters) caused by Plasmopara viticola, and rank the efficiency of different resistance components in disease suppression. We use an epidemiological simulation model to integrate the effect of four components of partial resistance, expressed as relative resistance parameters, i.e. infection efficiency (RRIE), latency period (RRLP), sporulation (RRSP), and infectious period (RRIP). Both the individual and combined effect of these components of resistance on downy mildew epidemics are evaluated through a sensitivity analysis. A comparison of simulation runs in different scenarios of disease conduciveness using experimental measurements of components of partial resistance for 16 different grapevine varieties is also performed. Increasing values of RR parameters led to a suppression of disease progress on foliage. The strongest reduction of epidemics on foliage is generated by increases in RRIE, followed by RRSP, RRIP, and last by RRLP. The effect of partial resistance on epidemics is more conspicuous in a scenario of limited disease conduciveness. The strongest suppressive effect of simulated epidemics on clusters is associated with RRIE, and the lowest effect with RRLP, with similar effects of increasing values of RRIP and RRSP. The use of experimentally measured relative resistance parameters to run simulated epidemics shows a reduction of the area under the disease progress curve from 4 × 105 (on a susceptible reference grapevine variety) to 4 × 102 (on cv. Bronner), i.e. a reduction of disease by 1000. The simulation of the varietal effect in intermediate and less favourable scenarios of disease conduciveness strongly suppresses the epidemic on foliage and limits disease on clusters to very low levels. Deploying partial host plant resistance in environments that are not strongly conducive to downy mildew epidemics could represent an effective use of partial resistance.

scholarly journals Fungicides for Control of Downy Mildew on Pickling Cucumber in Michigan

2019 ◽  
Vol 20 (3) ◽  
pp. 165-169 ◽  
Author(s):  
Katelyn E. Goldenhar ◽  
Mary K. Hausbeck
Keyword(s):  
Downy Mildew ◽  
Untreated Control ◽  
Field Studies ◽  
Pseudoperonospora Cubensis ◽  
Relative Area ◽  
Disease Progress Curve ◽  
Cucurbit Downy Mildew ◽  
Disease Progress ◽  
Pickling Cucumber ◽  
Progress Curve

Michigan growers rely on fungicides to limit cucurbit downy mildew (CDM), incited by Pseudoperonospora cubensis; resistance of the pathogen to fungicides is a concern. We evaluated fungicides against CDM in Michigan field studies from 2015 to 2017. According to the relative area under the disease progress curve (rAUDPC), in 2015, mandipropamid, propamocarb, fluxapyroxad/pyraclostrobin, copper octanoate, and dimethomorph resulted in disease levels similar to the control. These treatments, along with cymoxanil, were similar to the control in 2016. Fungicides that were ineffective during 2015 and 2016 did not limit CDM in 2017. Famoxadone/cymoxanil and fluopicolide did not limit CDM in 2017. Each year, the following treatments were similar for disease based on rAUDPC data: oxathiapiprolin applied alone or premixed with chlorothalonil or mandipropamid, ametoctradin/dimethomorph, fluazinam, mancozeb/zoxamide, cyazofamid, and ethaboxam. An exception occurred in 2017, when ethaboxam was less effective than fluazinam, oxathiapiprolin/chlorothalonil, and oxathiapiprolin/mandipropamid. Mancozeb and chlorothalonil treatments were similar in 2015 and 2017, according to rAUDPC data. In 2017, yields were increased for oxathiapiprolin/chlorothalonil, oxathiapiprolin/mandipropamid, mancozeb, ametoctradin/dimethomorph, mancozeb/zoxamide, ethaboxam, cyazofamid, chlorothalonil, and fluazinam compared with the untreated control.

scholarly journals Field Response of Cucurbit Hosts to Pseudoperonospora cubensis in Michigan

Plant Disease ◽  
2015 ◽  
Vol 99 (5) ◽  
pp. 676-682 ◽  
Author(s):  
M. C. Cespedes-Sanchez ◽  
R. P. Naegele ◽  
C. S. Kousik ◽  
M. K. Hausbeck
Keyword(s):  
Downy Mildew ◽  
Cucumis Melo ◽  
Disease Onset ◽  
Research Field ◽  
Pseudoperonospora Cubensis ◽  
Plant Introductions ◽  
Disease Progress ◽  
Pickling Cucumber ◽  
Progress Curve ◽  
Significant Disease

Downy mildew, caused by Pseudoperonospora cubensis, is a severe foliar disease of many cucurbit crops worldwide. Forty-one cucurbit cultigens (commercial cultivars and plant introductions) from five genera (Cucumis, Citrullus, Cucurbita, Lagenaria, and Luffa) were assessed for susceptibility to P. cubensis in a research field exposed to natural inoculum in Michigan. Eight cultigens from a differential set for pathotype determination were included within the 41 cultigens to detect changes in dominant P. cubensis pathotypes present. No pathotype differences were found between 2010 and 2011. Cucumis melo cultigen MR-1 was less susceptible to Michigan P. cubensis populations than other C. melo cultigens. No symptoms or signs of infection were detected on cultigens of Cucurbita moschata and C. pepo. Disease onset was later in 2011 than 2010; greater than 90% disease severity in pickling cucumber ‘Vlaspik’ was observed in both years. This study confirmed that Cucumis is the most susceptible cucurbit genus, while Citrullus and Cucurbita cultigens were the least susceptible genera to populations of P. cubensis in Michigan. Area under the disease progress curve values indicated that disease progress was limited on all Citrullus cultigens compared with Cucumis cultigens, and pathogen sporulation was not detected under field conditions. Future studies should evaluate the ability of a reduced fungicide program to control downy mildew on less susceptible Cucumis melo ‘Edisto 47’, ‘Primo’, ‘Athena’, ‘Strike’, ‘Ananas’, ‘Banana’, and ‘Tam-Dew’. Many of the melon cultivars evaluated were selected on the basis of reported resistance to downy mildew, yet they showed significant disease symptoms. It is important to evaluate candidate cultigens for resistance to local P. cubensis populations.

scholarly journals FIELD INOCULATION TESTS TO QUANTIFY RESISTANCE IN SPINACH TO RACES 3 AND 4 OF DOWNY MILDEW

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 598b-598
Author(s):  
L.P. Brandenberger ◽  
J.C. Correll ◽  
T.E. Morelock ◽  
R.W. McNew
Keyword(s):  
Downy Mildew ◽  
Disease Severity ◽  
Leaf Surface ◽  
Field Inoculation ◽  
Disease Progress Curve ◽  
Disease Progress ◽  
Progress Curve

Resistance to race 3 and 4 of downy mildew (Peronospora farinosa f.sp. spinaciae) was examined in separate field inoculation tests. Three Arkansas cultivars and three other commercial spinach cultivars were compared by periodically scoring individual leaves for disease severity 7 to 28 days after inoculation. Leaves were scored on a 0 to 6 scale with 0 = 0% of the leaf surface being covered with sporulation and 6 = 90-100%. Resistance was evaluated by comparing disease ratings on a given day as well as the area under the disease progress curve. Arkansas spinach cultivars exhibited significantly lower disease severity ratings in field inoculation tests for all sample dates for both races 3 and 4 when compared to known susceptible cultivars.

scholarly journals Adaptability and stability of soybean advanced lines of semi early cycle for rust resistance

2012 ◽  
Vol 12 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Juliana Araújo Santos Martins ◽  
Fernando Cézar Juliatti
Keyword(s):  
Partial Resistance ◽  
Block Design ◽  
Research Work ◽  
Visual Assessment ◽  
Disease Progress ◽  
Growing Seasons ◽  
Progress Curve ◽  
Randomized Complete Block Design ◽  
Rust Severity ◽  
The Mean

This research work was carried out to verify the adaptability and phenotypic stability of soybean inbred lines of semi early cycle, using rust severity as the selection trait for partial resistance. The strains were evaluated during the growing seasons of 2007/08 and 2008/09, in the locations of Uberlândia and Uberaba, MG, Campo Alegre de Goiás and Senador Canedo, GO, using a randomized complete block design with three replications. Rust severity was evaluated by visual assessment of the leaflets at the medial third of five plants in each plot. By using disease severity, it was estimated: the mean absolute rate of disease progress (r), the area under the disease progress curve (AUDPC) and the partial resistance factor (PRF). Adaptability and stability of the strains were estimated by the methods proposed by Eberhart and Russell, as well as by the AMMI method. It was found that the strains which were the most resistant to rust, in general, also showed the best adaptability and stability.

scholarly journals Management Strategies for Barley Yellow Dwarf on Winter Wheat in Kansas

2016 ◽  
Vol 17 (2) ◽  
pp. 122-127 ◽  
Author(s):  
William W. Bockus ◽  
Erick D. De Wolf ◽  
Timothy C. Todd
Keyword(s):  
Winter Wheat ◽  
Management Practices ◽  
Field Experiments ◽  
Management Strategies ◽  
Yellow Dwarf ◽  
Yield Losses ◽  
Disease Progress ◽  
Barley Yellow Dwarf ◽  
Progress Curve ◽  
The Impact

Barley yellow dwarf (BYD) is one of the most important wheat diseases in the state of Kansas. Several methods of disease management have been recommended to mitigate losses from BYD including the use of seed-treatment insecticides, delayed planting of winter wheat, and deploying cultivars with resistance to BYD. The goal of this research was to quantify the impact of these three management strategies, alone and in combination, on BYD disease progress and grain yields in Kansas. When field experiments were averaged over four years, treating seed with the insecticide imidacloprid (Gaucho) reduced the daily increase in the area under the disease progress curve (AUDPC) by 35.0% and corresponding yield losses from BYD by 16.4%. Compared with early planting, late planting reduced AUDPC by 47.9% and corresponding yield losses by 57.5%. Planting a moderately resistant cultivar reduced AUDPC by 80.9% and corresponding yield losses by 72.6% compared with a susceptible cultivar. When all three BYD management methods were combined, BYD was reduced by 95.2% and yield losses reduced by 97.1% when compared with not using any of the management methods. Therefore, integrating management practices can result in high levels of control of BYD in Kansas. Accepted for publication 4 May 2016. Published 7 June 2016.

MicroRNA-520c-3p Modulates Doxorubicin-Chemosensitivity in HepG2 Cells

2020 ◽  
Vol 21 (2) ◽  
pp. 237-245 ◽  
Author(s):  
Mohamed A. Ragheb ◽  
Marwa H. Soliman ◽  
Emad M. Elzayat ◽  
Mervat S. Mohamed ◽  
Nada El-Ekiaby ◽  
...  
Keyword(s):  
Hepg2 Cells ◽  
Therapeutic Strategy ◽  
Suppressive Effect ◽  
Expression Level ◽  
Tumor Suppressor Function ◽  
Protein Expression Level ◽  
Blot Technique ◽  
Induction Of Apoptosis ◽  
The Impact

Background: Doxorubicin (DOX) is the most common drugs used in cancer therapy, including Hepatocellular Carcinoma (HCC). Drug resistance, is one of chemotherapy’s significant problems. Emerging studies have shown that microRNAs (miRNAs) could participate in regulating this mechanism. Nevertheless, the impact of miRNAs on HCC chemoresistance is still enigmatic. Objective: Investigating the role of miR-520c-3p in enhancement of anti-tumor effect of DOX against HepG2 cells. Methods: Expression profile for liver related miRNAs (384 miRNAs) has been analyzed on HepG2 cells treated with DOX using qRT-PCR. miR-520c-3p, the most deregulated miRNA, was selected for combination treatment with DOX. Expression level for LEF1, CDK2, CDH1, VIM, Mcl-1 and TP53 was evaluated in miR-520c-3p transfected cells. Cell viability, colony formation, wound healing as well as apoptosis assays have been demonstrated. Furthermore, Mcl-1 protein level was measured using western blot technique. Results: The present data indicated that miR-520c-3p overexpression could render HepG2 cells chemo-sensitive to DOX through enhancing its suppressive effects on proliferation, migration, and induction of apoptosis. The suppressive effect of miR-520c-3p involved altering the expression levels of some key regulators of cell cycle, proliferation, migration and apoptosis including LEF1, CDK2, CDH1, VIM, Mcl-1 and TP53. Interestingly, Mcl-1 was found to be one of the potential targets of miR-520c-3p, and its protein expression level was down-regulated upon miR-520c-3p overexpression. Conclusion: Our data referred to the tumor suppressor function of miR-520c-3p that could modulate chemosensitivity of HepG2 cells toward DOX treatment, providing a promising therapeutic strategy in HCC.

scholarly journals Impact of public health interventions to curb SARS-CoV-2 spread assessed by an evidence-educated Delphi panel and tailored SEIR model

2021 ◽  
Author(s):  
Bernd Brüggenjürgen ◽  
Hans-Peter Stricker ◽  
Lilian Krist ◽  
Miriam Ortiz ◽  
Thomas Reinhold ◽  
...  
Keyword(s):  
Public Health ◽  
Transmission Rate ◽  
Latency Period ◽  
Policy Decision ◽  
Sensitivity Analyses ◽  
Delphi Panel ◽  
Time Step ◽  
Seir Model ◽  
Health Policy Decision ◽  
The Impact

Abstract Aim To use a Delphi-panel-based assessment of the effectiveness of different non-pharmaceutical interventions (NPI) in order to retrospectively approximate and to prospectively predict the SARS-CoV-2 pandemic progression via a SEIR model (susceptible, exposed, infectious, removed). Methods We applied an evidence-educated Delphi-panel approach to elicit the impact of NPIs on the SARS-CoV-2 transmission rate R0 in Germany. Effectiveness was defined as the product of efficacy and compliance. A discrete, deterministic SEIR model with time step of 1 day, a latency period of 1.8 days, duration of infectiousness of 5 days, and a share of the total population of 15% assumed to be protected by immunity was developed in order to estimate the impact of selected NPI measures on the course of the pandemic. The model was populated with the Delphi-panel results and varied in sensitivity analyses. Results Efficacy and compliance estimates for the three most effective NPIs were as follows: test and isolate 49% (efficacy)/78% (compliance), keeping distance 42%/74%, personal protection masks (cloth masks or other face masks) 33%/79%. Applying all NPI effectiveness estimates to the SEIR model resulted in a valid replication of reported occurrence of the German SARS-CoV-2 pandemic. A combination of four NPIs at consented compliance rates might curb the CoViD-19 pandemic. Conclusion Employing an evidence-educated Delphi-panel approach can support SARS-CoV-2 modelling. Future curbing scenarios require a combination of NPIs. A Delphi-panel-based NPI assessment and modelling might support public health policy decision making by informing sequence and number of needed public health measures.

scholarly journals Integrated Management of Downy Mildew on Slicing Cucumber With Fungicides and Host Resistance But Not Trellising

Plant Disease ◽  
2019 ◽  
Vol 103 (10) ◽  
pp. 2592-2598
Author(s):  
Anthony P. Keinath
Keyword(s):  
Downy Mildew ◽  
Host Resistance ◽  
Management Practices ◽  
Integrated Management ◽  
Cultivar Resistance ◽  
Fall Season ◽  
Fungicide Treatment ◽  
Progress Curve ◽  
Management Techniques ◽  
The Mean

The objective of this study was to evaluate fungicide applications, host resistance, and trellising, alone and in combination, as management practices for downy mildew on slicing cucumber. A split-split plot experimental design was used with three and four replications in spring and fall 2017, respectively. The whole-plot treatment was fungicide, four applications of chlorothalonil (Bravo Weather Stik 6SC) alternated with three applications of cyazofamid (Ranman 400SC), or water. Split plots were nontrellised or trellised with four strings supported by stakes. Split-split plots were cultivar Bristol, which is intermediately resistant to downy mildew, or cultivar Speedway, which is susceptible to downy mildew with similar parentage as Bristol. In both seasons, area under the disease progress curve (AUDPC) values were lower with fungicides than water for both cultivars. In the spring, AUDPC for Bristol was lower than for Speedway regardless of fungicide treatment. In the fall, Bristol had a lower AUDPC than Speedway with fungicides, but the AUDPC did not differ between the two cultivars with water. The mean AUDPC for trellised plants (376.2) was lower than for nontrellised plants (434.0; P = 0.007). Fungicide applications increased marketable and total fruit weights in both seasons (P ≤ 0.0002). Marketable weight with fungicides was almost double (93% greater) the marketable weight with water. Marketable weight was 55% greater for Bristol than for Speedway in spring, but yields did not differ between cultivars in fall (season-by-cultivar interaction, P ≤ 0.0003). Because trellising had no effect on marketable yields (P = 0.11), trellising is not recommended for managing downy mildew on slicing cucumber. Of the three management techniques examined, fungicides had the largest effects on disease and yields, followed by cultivar resistance.

scholarly journals Management of Daylily Rust With Different Fungicides and Fungicide Combinations

2017 ◽  
Vol 18 (3) ◽  
pp. 162-165 ◽  
Author(s):  
Robert S. Emmitt ◽  
James W. Buck
Keyword(s):  
United States ◽  
Disease Management ◽  
Disease Severity ◽  
Low Cost ◽  
Single Application ◽  
Southeast United States ◽  
Disease Progress Curve ◽  
Disease Progress ◽  
Progress Curve ◽  
Disease Pressure

Production nurseries and daylily hybridizers in the southeast United States rely on the use of fungicides to manage daylily rust, caused by the fungus Puccinia hemerocallidis. Foliar sprays of pyraclostrobin, flutolanil, tebuconazole, myclobutanil, chlorothalonil, mancozeb, pyraclostrobin + boscalid, flutolanil + tebuconazole, flutolanil + myclobutanil, flutolanil + chlorothalonil, and flutolanil + mancozeb applied on 14-day intervals, and a nontreated control, were evaluated under high disease pressure at three locations in Griffin, GA, in 2015. Tebuconazole or the tebuconazole + flutolanil treatment consistently had the lowest area under the disease progress curve (AUDPC) of the treatments. The addition of flutolanil to chlorothalonil or mancozeb did not improve rust control and no difference in disease severity was observed in any treatment containing contact fungicides on all assessment dates. Single application costs ranged from $10.21 to $95.96 with tebuconazole providing excellent disease management at a relatively low cost per application ($13.90).

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