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.

scholarly journals Chemical and biological control of Fusarium species involved in garlic dry rot at early crop stages

2021 ◽  
Author(s):  
Letizia Mondani ◽  
Giorgio Chiusa ◽  
Paola Battilani
Keyword(s):  
Growth Inhibition ◽  
Fusarium Species ◽  
Maximum Growth ◽  
Severity Index ◽  
Field Application ◽  
Dry Rot ◽  
Great Capacity ◽  
Chemical Products

AbstractThe aim of the study was to test in vitro and in vivo the efficacy of triazoles and biocontrol agents (BCAs) against Fusarium proliferatum and F. oxysporum, the former signaled as the main causal agent of garlic dry rot and the latter also involved. In vitro trials were organized using potato dextrose agar with added chemicals or BCAs inoculated with selected F. proliferatum and F. oxysporum. Garlic cloves were dipped before sowing in suspensions prepared with the fungicides showing the best performances in vitro; then they were dipped in Fusaria suspension before sowing. In in vitro trials, the maximum Fusaria growth inhibition was performed by Propiconazole + Prochloraz (100%), followed by Tebuconazole (88.9%). BCAs showed great capacity to control Fusaria, with a maximum growth inhibition of 80% (Trichoderma harzianum + T. gamsii). In vivo bacterial BCAs showed a similar capacity to control F. proliferatum and F. oxysporum compared to chemical products (mean of severity index 18.6% and 11.7%, respectively). In vivo results confirmed the in vitro performances, except for Trichoderma, which had the worst performances in vivo. Therefore, the results are preliminary but promising for future field application.

scholarly journals Pathogenicity of Fusarium species associated with crown and root rot of wheat (Triticum aestivum) under different condition

2019 ◽  
Vol 7 (1) ◽  
pp. 1-9
Author(s):  
Bareen Sidqi Shareef Al-Tovi ◽  
Raed Abduljabbar Haleem
Keyword(s):  
Disease Severity ◽  
Root Rot ◽  
Field Experiments ◽  
Fusarium Species ◽  
Test Tube ◽  
Spore Suspension ◽  
Wheat Crop ◽  
Pathogenicity Test ◽  
Crown And Root Rot

This study was conducted to test the pathogenicity of Fusarium species, the causes of crown and root rot disease of wheat crop, under three different conditions (Laboratory, Greenhouse and Field) and to show the best method for pathogenicity among different conditions. Pathogenicity test of six isolates of Fusarium species (F. graminearum, F. oxysporum, F. avenaceum, F. nivale, F. solani and F. udum) was tested on durum (Simeto) cultivar of wheat by test tube method in the laboratory, the tested fungi had substantial effect on seed germination. F. oxysporum showed the highest germination failure (44.44%) which significantly differed with other species. In the greenhouse, seedlings were inoculated by spore suspension at the base of each plant stem. The most virulent fungus after 35 days of inoculation was F. oxysporum (0.78) followed by F. solani (0.70) and F. graminearum (0.66), while the lowest disease severity was recorded by F. udum (0.16). Also in the field pathogenicity experiments of three Fusarium species (F. graminearum, F. oxysporum and F. solani) were performed on a durum (Simeto) and soft (Cham6) cultivars. Spore suspension was applied at the 2- to 3-leaf Zadoks’s growth stage. Disease severity was calculated at two stages of wheat growth (Booting and Ripening).The most virulent fungus was F. graminearum (0.42) that was significantly different from  other fungi. This work indicated that F. graminearum, F. oxysporum and F. solani showed higher infection than remaining tested species under threeconditions. Pathogenicity test in laboratory by test tube method (In-vitro) appeared more effective than greenhouse and field experiments

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).

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 The Cytopathic Effect of Different Toxin Concentrations From Different Clostridioides difficile Sequence Types Strains in Vero Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Zohar Hamo ◽  
Maya Azrad ◽  
Boris Fichtman ◽  
Avi Peretz
Keyword(s):  
Disease Severity ◽  
Cytopathic Effect ◽  
Vero Cells ◽  
Bacterial Strains ◽  
Host Immune Responses ◽  
Clostridioides Difficile ◽  
Cell Counts ◽  
Healthcare Associated ◽  
Sequence Types

Clostridioides difficile is one of the leading causes of healthcare-associated diarrhea, with severity ranging from mild, self-limiting disease, to life-threatening toxic megacolon. C. difficile infection (CDI) pathogenesis is mediated by the TcdA and TcdB toxins. This work aimed to draw correlations between toxin levels, bacterial strains, and disease severity in 63 CDI patients. C. difficile typing was performed by multi-locus sequence types (MLST). Toxin concentrations were measured using the TOX A/B test. In addition, cell cytotoxicity assay was performed following Vero cell exposure to stool extracts (24 h). The most prevalent sequence types (ST) were ST2, ST4, ST6, ST13, ST37, ST42, and ST104, with highest toxin levels produced by ST42 and ST104 (302.5 and 297.1 ng/ml, respectively). These strains had a stronger cytopathic effect (CPE) on Vero cells as compared to strains with lower toxin concentrations (p < 0.001), as manifested by lower cell counts and higher percentages of cell rounding and adhesion loss. Although no association was found between ST, toxin concentrations, and disease severity, a diverse in vitro effect of different STs on the viability and activity of Vero cells was observed. These findings suggest that disease severity is affected by both host immune responses and by bacterial characteristics.

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.

scholarly journals Potential of Bacillus subtilis for controlling bacterial leaf blight pathogen in rice

Food Research ◽  
2020 ◽  
Vol 4 (S5) ◽  
pp. 124-130
Author(s):  
K.S. Ku Asmah ◽  
Z. Sapak
Keyword(s):  
Bacillus Subtilis ◽  
Disease Severity ◽  
Severe Disease ◽  
Severity Index ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
In Vivo Studies ◽  
Disease Severity Index ◽  
Rice Plants

Bacterial leaf blight (BLB) of rice is an economically important disease caused by Xanthomonas oryzae pv. oryzae (Xoo) throughout the world. To control this disease, bacterial isolate of Bacillus subtilis UiTMB1 was screened for the antagonistic activity against the pathogen in vitro and in vivo studies. A bacterial assay and detached leaf technique were used to evaluate the potential of the bacterium against BLB pathogen in the laboratory. Meanwhile, the glasshouse study was conducted to further examine the aptitudes of the isolate on the disease control and growth-promoting of rice plants. The findings revealed that B. subtilis UiTMB1 is able to control the disease and enhance the growth of rice plants. Rice plants treated with B. subtilis UiTMB1 before being inoculated with BLB pathogen showed less severe disease symptoms with low disease severity index of 3.43 compared to rice plants without B. subtilis UiTMB1 with high disease severity index of 8.4. Besides controlling the disease, B. subtilis UiTMB1 was also promoting plant height, chlorophyll content, number of tillers and biomass of rice plants.

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.

Evaluation of Antibacterial Activity of Acer syriacum by Bioautography Method

1970 ◽  
Vol 9 (2) ◽  
pp. 3215-3219
Author(s):  
B. Al Asfour ◽  
R. Al-kayali ◽  
A. Kitaz
Keyword(s):  
Antibacterial Activity ◽  
Methanolic Extract ◽  
Ethyl Acetate Extract ◽  
Diffusion Method ◽  
Klebsiella Pneumonia ◽  
Bacterial Strains ◽  
In Vitro Antibacterial Activity ◽  
Inhibition Zones ◽  
Layer Chromatography

antibacterial activity of leaves, fruits and bark of acer syriacum was evaluated against both negative and positive gram bacterial strains. The powder of above parts were sequentially extracted with aqueous methanol 80%, acetone and petroleumether by maceration. The in vitro antibacterial activity of A. syriacum extracts (in concentration of 200 mg/mL) was performed by agar well diffusion method. Among the tested extracts, leaves methanolic extract has shown the highest growth inhibition. Further, the extract was fractionated, separated by thin layer chromatography (TLC) and submitted to bioautography. the results indicate that the ethyl acetate extract had  the most efficient antibacterial  compounds that displayed inhibition zones (25 mm) against Staphylococcus aureus ATCC25923 and (28mm) against Klebsiella pneumonia ATCC700603. the clear zones were located at RF= 0.15.

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