scholarly journals Effects of Herbicides on Sclerotinia Crown and Stem Rot of Alfalfa

Plant Disease ◽  
1997 ◽  
Vol 81 (7) ◽  
pp. 787-790 ◽  
Author(s):  
S. L. Reichard ◽  
R. M. Sulc ◽  
L. H. Rhodes ◽  
M. M. Loux
Keyword(s):  
Disease Severity ◽  
Residual Effect ◽  
Severity Index ◽  
Stem Rot ◽  
Controlled Environment ◽  
Herbicide Application ◽  
Infection Period ◽  
Seedling Inoculation ◽  
Herbicide Treatments ◽  
Environment Study

This study was conducted to determine whether herbicides and adjuvants registered for poste-mergence use in alfalfa have an effect on Sclerotinia crown and stem rot (SCSR). In a controlled environment, disease severity index (DSI) of alfalfa seedlings was reduced by pronamide and 2,4-DB compared with the untreated control, whereas bromoxynil and 13% sethoxydim + petroleum-based adjuvant (PBA) increased DSI. In the field, disease severity in all herbicide treatments was similar to that in untreated alfalfa. In a second controlled-environment study, pronamide and 2,4-DB reduced DSI compared with the no herbicide control when seedlings were inoculated 1 day after herbicide application, but this protective effect was not observed when seedlings were inoculated 8 days or longer after herbicide application. The results demonstrate that several herbicides are capable of suppressing or enhancing SCSR severity in a controlled environment if seedling inoculation occurs soon after herbicide application; however, the residual effect of these herbicides on SCSR appeared to be much shorter than the 4- to 6-week infection period occurring in the field.

scholarly journals Case Study of an Epidemiological Approach Dissecting Historical Soybean Sclerotinia Stem Rot Observations and Identifying Environmental Predictors of Epidemics and Yield Loss

2018 ◽  
Vol 108 (4) ◽  
pp. 469-478 ◽  
Author(s):  
Mamadou L. Fall ◽  
John F. Boyse ◽  
Dechun Wang ◽  
Jaime F. Willbur ◽  
Damon L. Smith ◽  
...  
Keyword(s):  
Disease Severity ◽  
Yield Loss ◽  
Historical Data ◽  
Severity Index ◽  
Stem Rot ◽  
Total Precipitation ◽  
Disease Severity Index ◽  
Sclerotinia Stem Rot ◽  
Environmental Predictors ◽  
Epidemiological Approach

Sclerotinia sclerotiorum is a significant threat to soybean production worldwide. In this study, an epidemiological approach was used to examine 11 years of historical data from a soybean management performance trial in order to advance our understanding of Sclerotinia stem rot (SSR) development and to identify environmental predictors of SSR epidemics and associated yield losses. Recursive partitioning analysis suggested that average air temperature and total precipitation in July were the most significant variables associated with disease severity. High levels of SSR disease severity index were observed when the average temperature in July was below 19.5°C and total precipitation in July was moderate, between 20 and 108.5 mm. A biphasic sigmoidal curve accurately described the relationship between SSR disease severity index (DSI) and yield, with a DSI threshold of 22, below which minimal yield loss was observed. A 10% increase in the DSI, from 22.0 to 24.2, led to an 11% decrease in yield, from 3,308.14 to 2,951.29 kg/ha. Also, a yield threshold (3,353 kg/ha) that was higher than the annual U.S. average soybean yield (3,039.7 kg/ha) was suggested as an expected yield under low or no SSR pressure in the U.S. Midwest. These thresholds can allow soybean stakeholders to assess the value of disease control and establish an SSR baseline for cost-effective management to protect yields. Because S. sclerotiorum has more than 400 plant host species, and because having quantitative information concerning crop losses is crucial for decision making, this study shows the usefulness of historical data on SSR and, hence, can serve as a model in other SSR pathosystems (canola, dry bean, potato, pea, and so on).

Composts containing fluorescent pseudomonads suppress fusarium root and stem rot development on greenhouse cucumber

2010 ◽  
Vol 56 (11) ◽  
pp. 896-905 ◽  
Author(s):  
Geoffrey G. Bradley ◽  
Zamir K. Punja
Keyword(s):  
Disease Severity ◽  
Total Population ◽  
Fusarium Species ◽  
Severity Index ◽  
Stem Rot ◽  
Bacterial Strains ◽  
Growth Room ◽  
Greenhouse Cucumber ◽  
Layer Chromatography

Three composts (Ball, dairy, and greenhouse) were tested for the ability to suppress the development of Fusarium root and stem rot (caused by Fusarium oxysporum f. sp. radicis-cucumerinum) on greenhouse cucumber. Dairy and greenhouse composts significantly reduced disease severity (P = 0.05), while Ball compost had no effect. Assessment of total culturable microbes in the composts showed a positive relationship between disease suppressive ability and total population levels of pseudomonads. In vitro antagonism assays between compost-isolated bacterial strains and the pathogen showed that strains of Pseudomonas aeruginosa exhibited the greatest antagonism. In growth room trials, strains of P. aeruginosa and nonantagonistic Pseudomonas maculicola , plus 2 biocontrol strains of Pseudomonas fluorescens , were tested for their ability to reduce (i) survival of F. oxysporum, (ii) colonization of plants by the pathogen, and (iii) disease severity. Cucumber seedlings grown in compost receiving P. aeruginosa and P. fluorescens had reduced disease severity index scores after 8 weeks compared with control plants without bacteria. Internal stem colonization by F. oxysporum was significantly reduced by P. aeruginosa. The bacteria colonized plant roots at 1.9 × 106 ± 0.73 × 106CFU·(g root tissue)–1and survival was >107 CFU·(g compost)–1after 6 weeks. The locus for 2,4-diacetylphloroglucinol production was detected by Southern blot analysis and confirmed by PCR. The production of the antibiotic 2,4-diacetylphloroglucinol in liquid culture by P. aeruginosa was confirmed by thin layer chromatography. These results demonstrate that composts containing antibiotic-producing P. aeruginosa have the potential to suppress diseases caused by Fusarium species.

scholarly journals Greenhouse Cucumber Cultivars Differ in Susceptibility to Fusarium Root and Stem Rot

2004 ◽  
Vol 14 (2) ◽  
pp. 240-242 ◽  
Author(s):  
Steve Rose ◽  
Zamir K. Punja
Keyword(s):  
Fusarium Oxysporum ◽  
Disease Severity ◽  
Severity Index ◽  
Stem Rot ◽  
Disease Severity Index ◽  
Plant Mortality ◽  
Breeding Lines ◽  
The Third ◽  
Enhanced Resistance ◽  
Greenhouse Cucumber

Eighteen cucumber (Cucumis sativus L.) cultivars (long English type) were screened for their susceptibility to fusarium root and stem rot caused by Fusarium oxysporum Schlechtend.: Fr. f.sp. radicis-cucumerinum D.J. Vakalounakis using seedlings at the third true-leaf stage. Roots were trimmed and dipped into a spore suspension (105 spores/mL) of the pathogen and the plants were re-potted. A disease severity index (DSI) was used to assess disease responses 4 or 8 weeks later based on plant mortality and the height of surviving plants compared to the noninoculated controls. `Sienna', `Amazing' and `Dominica' were most susceptible to infection and the resulting DSI values were significantly (P ≤ 0.05) higher compared to noninoculated control plants. The cultivars `Korinda', `Euphoria' and `Aviance' displayed significantly lower DSI values which were not significantly different from noninoculated control plants. The remaining 12 cultivars displayed DSI values which were intermediate between the above two classes of responses. The results from this study indicate there is the potential to identify and develop cultivars and breeding lines of greenhouse cucumbers with enhanced resistance to fusarium root and stem rot.

Meta-Analytic and Economic Approaches for Evaluation of Pesticide Impact on Sclerotinia Stem Rot Control and Soybean Yield in the North Central United States

2019 ◽  
Vol 109 (7) ◽  
pp. 1157-1170 ◽  
Author(s):  
Jaime F. Willbur ◽  
Paul D. Mitchell ◽  
Mamadou L. Fall ◽  
Adam M. Byrne ◽  
Scott A. Chapman ◽  
...  
Keyword(s):  
Disease Severity ◽  
Yield Loss ◽  
Severity Index ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Soybean Yield ◽  
The North ◽  
Central United States ◽  
Meta Analyses ◽  
The Impact

As complete host resistance in soybean has not been achieved, Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum continues to be of major economic concern for farmers. Thus, chemical control remains a prevalent disease management strategy. Pesticide evaluations were conducted in Illinois, Iowa, Michigan, Minnesota, New Jersey, and Wisconsin from 2009 to 2016, for a total of 25 site-years (n = 2,057 plot-level data points). These studies were used in network meta-analyses to evaluate the impact of 10 popular pesticide active ingredients, and seven common application timings on SSR control and yield benefit, compared with not treating with a pesticide. Boscalid and picoxystrobin frequently offered the best reductions in disease severity and best yield benefit (P < 0.0001). Pesticide applications (one- or two-spray programs) made during the bloom period provided significant reductions in disease severity index (DIX) (P < 0.0001) and led to significant yield benefits (P = 0.0009). Data from these studies were also used in nonlinear regression analyses to determine the effect of DIX on soybean yield. A three-parameter logistic model was found to best describe soybean yield loss (pseudo-R2 = 0.309). In modern soybean cultivars, yield loss due to SSR does not occur until 20 to 25% DIX, and considerable yield loss (−697 kg ha−1 or −10 bu acre−1) is observed at 68% DIX. Further analyses identified several pesticides and programs that resulted in greater than 60% probability for return on investment under high disease levels.

Influence of Selected Adjuvants on Disease Severity byPhoma herbarumon Dandelion (Taraxacum officinale)

1999 ◽  
Vol 13 (4) ◽  
pp. 675-679 ◽  
Author(s):  
Silke Neumann ◽  
Greg J. Boland
Keyword(s):  
Disease Severity ◽  
Triticum Durum ◽  
Guar Gum ◽  
Biological Control Agent ◽  
Taraxacum Officinale ◽  
Control Agent ◽  
Controlled Environment ◽  
Cyamopsis Tetragonoloba ◽  
Phoma Herbarum ◽  
Environment Study

Phoma herbarumwas evaluated as a potential biological control agent for dandelion (Taraxacum officinale) in turf. A preliminary controlled environment study identified selected adjuvants that enhanced disease severity byP. herbarum.Subsequently, these adjuvants were evaluated for disease enhancement under field conditions. Adjuvants evaluated included gluten flour, liposome, guar gum from ground guar (Cyamopsis tetragonoloba), durum (Triticum durum), and pectin. Regression analysis revealed a significant (P= 0.05) increase in disease severity byP. herbarumwhen formulated with gluten Hour, guar gum, or durum semolina compared to treatment with 20% mycelium in potato (Solanum tuberosum) dextrose broth (PDB) alone. No phytotoxicity to dandelion was observed among the adjuvant controls.

Biochemical basis of genotypic and bio-agent induced stem rot resistance in groundnut

2017 ◽  
Vol 40 (04) ◽  
Author(s):  
Riddhi H. Rajyaguru ◽  
Thirumalaisamy P. P. ◽  
Kirankumar G. Patel ◽  
Jignasha T. Thumar
Keyword(s):  
Disease Severity ◽  
Polyphenol Oxidase ◽  
Severity Index ◽  
Stem Rot ◽  
Systemic Resistance ◽  
Defense Enzymes ◽  
Disease Severity Index ◽  
Biochemical Basis ◽  
Catalase Peroxidase ◽  
Resistant Genotypes

Stem rot (Sclerotium rolfsii Sacc.) resistance in groundnut genotypes was due to activities of defense enzymes such as, catalase, peroxidase and polyphenol oxidase. Bio-agent, Bacillus amyloliquefaciens isolated from groundnut rhizosphere enhances the activities of defense enzymes through salicylic acid induced systemic resistance. In resistant genotypes (NRCGCS-19 and NRCGCS-319) higher activities of defense enzymes were recorded constitutively while in susceptible genotypes it was increased after bio-agent treatment. The activities of pathogenesis related-proteins viz., polygalacturonase and chitinase were registered in plants inoculated with S. rolfsii. Enzymes, catalase, peroxidase, polyphenol oxidase and chitinase showed strong negative correlation with disease severity index. However, the activity of polygalacturonase was directly related to disease severity index and inversely related to activity of chitinase. Hence, to obtain required levels of crop protection against S. rolfsii one has to grow either resistant genotypes or bio-agent treated susceptible genotypes.

Effect of crop rotation and soil amendments on Sclerotinia stem rot on soybean in two soils

2007 ◽  
Vol 87 (3) ◽  
pp. 605-614 ◽  
Author(s):  
G. Rousseau ◽  
S. Rioux ◽  
D. Dostaler
Keyword(s):  
Disease Severity ◽  
Crop Rotation ◽  
Redundancy Analysis ◽  
Sandy Loam ◽  
Soil Amendments ◽  
Severity Index ◽  
Stem Rot ◽  
Disease Severity Index ◽  
Clay Loam ◽  
Sclerotinia Stem Rot

The effect of 4-yr soybean rotations with corn (CCCS vs. CCSS vs. SSSS) and soil amendments (urban compost vs. mineral fertilizer) on Sclerotinia stem rot of soybean (disease severity index, apothecia number, sclerotia survival), caused by Sclerotinia sclerotiorum, was studied on two soils (clay loam and sandy loam) at Saint-Hyacinthe, in southwestern Québec, from 1999 to 2002. In 2002, the 3-yr-corn rotation had a significant effect on the disease severity index (DSI) at the clay loam site; DSI was greatly reduced by rotation (5.2%) compared with monoculture (44.3%). At the sandy loam site, an interaction between rotation and fertility amendments reduced DSI from 71.7% in the monoculture to 37.8% in the 3-yr-corn rotation amended with compost. Canonical redundancy analysis (RDA) of the DSI-apothecia matrix in 2002 confirmed the suppressiveness of the 3-yr-corn rotation and revealed a significant conducive effect on DSI of compost at the clay loam site. At the sandy loam site, RDA of the DSI-apothecia matrix confirmed suppressive interaction between corn-soybean rotations and compost amendment. Key words: Sclerotinia stem rot of soybean, crop rotation, urban compost, multiple regression, canonical redundancy analysis, permutations test

EVALUATION OF NONIONIC SURFACTANTS FOR CONTROL OF CLUBROOT OF CABBAGE USING BAREROOT AND PLUG TRANSPLANTS OF TWO CULTIVARS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 607b-607
Author(s):  
W. Tietjen ◽  
P.J. Nitzsche ◽  
W.P. Cowgill ◽  
M.H. Maletta ◽  
S.A. Johnston
Keyword(s):  
Brassica Oleracea ◽  
Disease Severity ◽  
Nonionic Surfactants ◽  
Plasmodiophora Brassicae ◽  
Severity Index ◽  
Effective Control ◽  
Disease Severity Index

`Market Prize' and `Bravo' cabbage (Brassica oleracea Var. capitata L.), transplanted as peat plug and bareroot plants into a field naturally infested with Plasmodiophora brassicae, Woronin, were treated immediately after planting with a liquid or a granular surfactant. APSA 80™, applied in transplant water, significantly reduced percent clubbing and disease severity index (DSI) compared to control treatments. Miller Soil Surfactant Granular™ did not significantly reduce percent clubbing or DSI. There was a significant effect of cultivar on percent clubbing and DSI. There was no significant effect of transplant type on percent clubbing or DSI. This year's study culminates five years of investigation of surfactants for clubroot control. Specific surfactants have proven to be an effective control of clubroot in cabbage. Chemical names used: nonylphenoxypolyethoxyethanol (APSA 80™); alpha-alkanoic-hydro omega-hydroxy poly (oxyethylene) (Miller Soil Surfactant Granular™).

scholarly journals A Weed Compaction Roller System for Use with Mechanical Herbicide Application

2006 ◽  
Vol 23 (1) ◽  
pp. 66-69 ◽  
Author(s):  
Adam H. Wiese ◽  
Daniel A. Netzer ◽  
Don E. Riemenschneider ◽  
Ronald S. Zalesny
Keyword(s):  
Tree Plantations ◽  
Diameter Growth ◽  
Herbicide Application ◽  
Treatment Combination ◽  
Invasive Weed ◽  
Vegetation Control ◽  
Growing Seasons ◽  
Herbicide Treatments ◽  
Roller System ◽  
The Cost

Abstract We designed, constructed, and field-tested a versatile and unique weed compaction roller system that can be used with mechanical herbicide application for invasive weed control in tree plantations, agronomic settings, and areas where localized flora and fauna are in danger of elimination from the landscape. The weed compaction roller system combined with herbicide application generally had greater vegetation control compared with using only herbicide treatments or the unsprayed control. The roller system-herbicide treatment combination showed substantial total vegetation control two growing seasons after application without impacting diameter growth of the crop trees, which supports the need for less frequent entries into the field. The cost of the roller system was approximately $300.00.

scholarly journals Association of Pathogenic Th17 Cells with the Disease Severity and Its Potential Implication for Biological Treatment Selection in Psoriasis Patients

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Cristina Aguilar-Flores ◽  
Octavio Castro-Escamilla ◽  
Elizabeth M. Ortega-Rocha ◽  
César Maldonado-García ◽  
Fermín Jurado-Santa Cruz ◽  
...  
Keyword(s):  
Disease Severity ◽  
Peripheral Blood ◽  
Th17 Cells ◽  
Life Quality ◽  
Severity Index ◽  
Experimental Models ◽  
Cutaneous Lesions ◽  
Potential Implication ◽  
Th17 Lymphocytes ◽  
Pasi Score

Psoriasis is an inflammatory autoimmune disease characterized by cutaneous lesions in plaques. It has been proposed that the immune response has a key role in the disease progression. Particularly, the Th17 cells through IL-17 can contribute to maintain the inflammatory process. The pathogenic Th17 phenotype has been described in human diseases and associated with high severity in inflammatory experimental models. However, it is not clear if the pathogenic phenotype could be present in the skin and peripheral blood as well as its possible association to severity in psoriasis. In the lesional skin, we found high infiltration of Th17 cells and the pathogenic phenotype, finding a correlation between the frequency of Th17 cells and the Psoriasis Area and Severity Index (PASI) score. In peripheral blood, we observed a pool of Th17 lymphocytes with potential to acquire pathogenic features. Interestingly, the percentage of pathogenic Th17 cells (CD4+ RORγt+ IFN-γ+) correlates with disease severity. Moreover, we distinguished three groups of patients based on their IL-17/IFN-γ production by Th17 lymphocytes, which seems to be related with a dynamic or stable potential to express these cytokines. Remarkably, we evaluated the cytokine production by Th17 cells as an immunological marker for the adequate selection of biologic therapy. We found that patients analyzed by this immunological approach and treated with antibodies against IL-17 and TNFα showed great improvement depicted by reduction in PASI and Dermatology Life Quality Index (DLQI) score as well as the percentage of Body Surface Area (BSA). Altogether, our results highlight the importance of the assessment of the pathogenic phenotype in Th17 cells as an immune personalized analysis with the potential to support the therapy choice in the clinical practice.

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