Evaluation of Wounds as a Factor to Infection of Cabbage by Ascospores of Sclerotinia sclerotiorum

Plant Disease ◽  
2000 ◽  
Vol 84 (3) ◽  
pp. 316-320 ◽  
Author(s):  
J. Hudyncia ◽  
H. D. Shew ◽  
B. R. Cody ◽  
M. A. Cubeta
Keyword(s):  
North Carolina ◽  
Sclerotinia Sclerotiorum ◽  
Disease Incidence ◽  
Selective Medium ◽  
Controlled Environment ◽  
Factors Associated ◽  
Progress Curve ◽  
Spore Trapping ◽  
Eastern North Carolina

A semi-selective medium was used to examine the aerobiology of ascospores of Sclerotinia sclerotiorum in five commercial cabbage fields in eastern North Carolina. Ascospores were present in all five fields from 26 September to 30 November. However, numbers of ascospores varied greatly depending on location, sampling date, and time. In general, peak ascospore deposition occurred between 11:00 A.M. and 1:00 P.M., with the number of colonies recovered ranging from 3 to 55/dish (9 cm in diameter). Peak ascospore numbers at all locations were found from mid- to late October, but a second, smaller peak was also evident at each location in late November. Information obtained was employed to evaluate the role of wounding in infection of cabbage by ascospores of S. sclerotiorum in controlled environmental chambers. A method for production and release of ascospores of S. sclerotiorum was employed in controlled-environment chambers for the inoculation of cabbage plants with one of three representative foliar wounds: a bruise, a cut, or a non-lethal freeze. Wounding treatments were applied to 7-week-old cabbage plants, misting was added to maintain continuous leaf wetness, and ascospores were released from apothecia twice daily for four consecutive days. Spore trapping with a semi-selective medium indicated that inoculum was evenly distributed within the chambers and deposition was similar to levels recorded in the field. At 31 days after inoculation, disease incidence ranged from 0% on the control to 96% on the freeze treatments. Freeze-treated plants showed the highest disease severity throughout the entire incubation period. Mean area under the disease progress curve of severity values were 0, 0.2, 34 and 60 for the control, cut, bruise, and freeze treatments, respectively. Results indicate that freeze and bruise injuries are important factors associated with infection of cabbage by S. sclerotiorum.

The role of fungi and nematodes as factors associated with death of white clover (Trifolium repens) stolons over summer in south-eastern Queensland

1977 ◽  
Vol 17 (88) ◽  
pp. 789 ◽  
Author(s):  
JAG Irwin ◽  
RM Jones
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Field Trials ◽  
Fungal Species ◽  
Parasitic Nematodes ◽  
Controlled Environment ◽  
Plant Parasitic Nematodes ◽  
Factors Associated ◽  
One Year

A series of laboratory and field trials examined the role of both fungi and nematodes in causing stolon death of white clover (Trifolium repens) which is typically encountered over summer/early autumn in sub-tropical coastal Queensland. Pythium middletonii was consistently isolated from necrotic stolons and roots of Trifolium spp. collected at a range of sites, and was the only fungal species isolated that was pathogenic to white clover seedlings in glasshouse tests. Under controlled environment conditions P. middletonii also caused a root and stolon rot of mature plants similar to that observed in the field. Preliminary studies suggested that some naturalized white clover strains are more resistant as seedlings than commercial white clover cultivars. In 1974-75 and 1975-76 fungicides were applied at monthly intervals over summer to grazed pastures at two sites. Stolon death was significantly reduced by fungicide at one site in one year. The possible role of plant parasitic nematodes in the decline syndrome was investigated in 1975 at three sites: the decline in clover was significantly reduced by nematicide at each site.

scholarly journals Clonality in Sclerotinia sclerotiorum on Infected Cabbage in Eastern North Carolina

1997 ◽  
Vol 87 (10) ◽  
pp. 1000-1004 ◽  
Author(s):  
M. A. Cubeta ◽  
B. R. Cody ◽  
Y. Kohli ◽  
L. M. Kohn
Keyword(s):  
North Carolina ◽  
Sclerotinia Sclerotiorum ◽  
Total Sample ◽  
Small Sample ◽  
Dna Fingerprint ◽  
Dna Fingerprints ◽  
The North ◽  
Mycelial Compatibility ◽  
Eastern North Carolina ◽  
Two Populations

Eighty-four isolates of Sclerotinia sclerotiorum from four cabbage production fields in North Carolina and 16 isolates from an experimental cabbage field plot in Louisiana were DNA-fingerprinted and tested for mycelial compatibility. In a comparison with 594 unique DNA fingerprints of S. sclerotiorum from Canadian canola, no fingerprints were shared among Canadian, North Carolina, and Louisiana populations. DNA fingerprints from the North Carolina sample were distinctive from those of the Canadian and Louisiana samples, with significantly more hybridizing fragments in the 7.7- to 18-kilobase range. Forty-one mycelial compatibility groups (MCGs) and 50 unique DNA fingerprints were identified from the North Carolina sample. Three MCGs and three fingerprints were identified from the Louisiana sample. From the North Carolina sample, 32 MCGs were each associated with a unique fingerprint; of these, there were 11 clones (i.e., cases in which two or more isolates belonged to the same MCG and shared the same DNA fingerprint). Six clones sampled from two or more fields represented approximately 29% of the total sample (24 of 84 isolates), with six clones recovered from fields 75 km apart. There were 10 cases in which one MCG was associated with more than one DNA fingerprint and two cases in which one DNA fingerprint was associated with more than one MCG. The small sample from Louisiana was strictly clonal. The North Carolina sample had a clonal component, but deviated from one-to-one association of MCG with DNA fingerprint to an extent consistent with more recombination or transposition than the other two populations sampled.

Response of dry bean white mould [Sclerotinia sclerotiorum (Lib.) de Bary, causal organism] to fungicides

2014 ◽  
Vol 94 (5) ◽  
pp. 905-910 ◽  
Author(s):  
K. J. Mahoney ◽  
C. M. McCreary ◽  
C. L. Gillard
Keyword(s):  
Bacillus Subtilis ◽  
Sclerotinia Sclerotiorum ◽  
Disease Incidence ◽  
Yield Potential ◽  
Causal Organism ◽  
Dry Bean ◽  
Thiophanate Methyl ◽  
White Mould ◽  
Progress Curve ◽  
Serious Disease

Mahoney, K. J., McCreary, C. M. and Gillard, C. L. 2014. Response of dry bean white mould [ Sclerotinia sclerotiorum (Lib.) de Bary, causal organism] to fungicides. Can. J. Plant Sci. 94: 905–910. White mould [Sclerotinia sclerotiorum (Lib.) de Bary, causal organism] is a serious disease of dry bean (Phaseolus vulgaris L.). Producers frequently rely on preventative fungicides, yet, this represents a significant production cost. Studies were conducted in 2009, 2010, and 2011 to determine fungicide efficacy under conditions optimized for white mould. Disease incidence×severity ratings were used to calculate the area under the disease progress curve (AUDPC). After harvest, a return on investment (ROI) was calculated. AUDPC values were similar across boscalid, fluazinam, fluopyram, and thiophanate-methyl and lower than Bacillus subtilis, CaCl2, and the untreated. Yield was greatest for fluazinam and fluopyram, followed by thiophanate-methyl. Bacillus subtilis and CaCl2 yields were similar to the untreated. In early-planted environments, using fluazinam and fluopyram resulted in a $500 ha−1 greater ROI than the untreated with $554 gained for every tonne per hectare of dry bean harvested. In late-planted environments, fluazinam and fluopyram averaged about $200 ha−1 greater ROI than the untreated and $494 was returned for every tonne per hectare of dry bean. When dry bean yield potential is reduced under conditions of increased white mould severity, profit margins become narrowed and producers may have to select fungicides that are both efficacious and economical.

scholarly journals Disease Development Following Infection of Tomato and Basil Foliage by Airborne Conidia of the Soilborne Pathogens Fusarium oxysporum f. sp. radicis-lycopersici and F. oxysporum f. sp. basilici

2000 ◽  
Vol 90 (12) ◽  
pp. 1322-1329 ◽  
Author(s):  
Y. Rekah ◽  
D. Shtienberg ◽  
J. Katan
Keyword(s):  
Fusarium Oxysporum ◽  
Disease Incidence ◽  
Selective Medium ◽  
Management Program ◽  
Causal Agent ◽  
Soilborne Pathogens ◽  
Tomato Plants ◽  
Pathogen Invasion ◽  
Crown And Root Rot

Fusarium oxysporum f. sp. radicis-lycopersici, the causal agent of Fusarium crown and root rot of tomato, and F. oxysporum f. sp. basilici, the causal agent of Fusarium wilt in basil, are soilborne pathogens capable of producing conspicuous masses of macroconidia along the stem. The role of the airborne propagules in the epidemics of the disease in tomato plants was studied. In the field, airborne propagules of F. oxysporum f. sp. radicis-lycopersici were trapped with a selective medium and their prevalence was determined. Plants grown in both covered and uncovered pots, detached from the field soil, and exposed to natural aerial inoculum developed typical symptoms (82 to 87% diseased plants). The distribution of inoculum in the growth medium in the pots also indicated the occurrence of foliage infection. In greenhouse, foliage and root inoculations were carried out with both tomato and basil and their respective pathogens. Temperature and duration of high relative humidity affected rate of colonization of tomato, but not of basil, by the respective pathogens. Disease incidence in foliage-inoculated plants reached 75 to 100%. In these plants, downward movement of the pathogens from the foliage to the crown and roots was observed. Wounding enhanced pathogen invasion and establishment in the foliage-inoculated plants. The sporulation of the two pathogens on stems, aerial dissemination, and foliage infection raise the need for foliage protection in addition to soil disinfestation, in the framework of an integrated disease management program.

scholarly journals Soybean Cultivar Responses to Sclerotinia sclerotiorum in Field and Controlled Environment Studies

Plant Disease ◽  
1998 ◽  
Vol 82 (11) ◽  
pp. 1264-1270 ◽  
Author(s):  
S. N. Wegulo ◽  
X. B. Yang ◽  
C. A. Martinson
Keyword(s):  
Oxalic Acid ◽  
Sclerotinia Sclerotiorum ◽  
Field Experiments ◽  
Disease Incidence ◽  
Pearson Correlation ◽  
Stem Rot ◽  
Controlled Environment ◽  
Soybean Cultivars ◽  
Detached Leaf

The responses of 12 soybean cultivars to Sclerotinia sclerotiorum were evaluated under field and controlled environment conditions. The 12 cultivars were planted in fields naturally or artificially infested with S. sclerotiorum and evaluated for disease incidence. In controlled environment studies, the cultivars were compared with respect to lesion size on detached leaves and stems inoculated with mycelial disks, incidence of stem rot following mycelial inoculation of foliage, lesion lengths on stems discolored by oxalic acid, and levels of soluble pigment(s) in stems. Significant differences (P ≤ 0.05) in disease incidence, lesion sizes, and levels of soluble pigment(s) were detected among the 12 cultivars in all evaluations, but ranking of cultivars varied among methods and experiments within methods. Corsoy 79 and S19-90 were consistently most resistant in all methods; whereas Kenwood, A2242, Bell, and Williams 82 were least resistant. Pearson correlation coefficients (R) for disease incidence between location years in field experiments (FE) ranged from 0.86 to 0.95. R values between FE and controlled environment experiments (CEE) ranged from 0.01 to 0.62 for detached leaf assays (DLA), -0.20 to 0.47 for lesion lengths on stems inoculated with mycelial disks (LLM), 0.38 to 0.45 for incidence of stem rot from mycelial inoculation of foliage (MIF), 0.08 to 0.66 for lesion lengths on stems discolored by oxalic acid (LLO), and -0.55 to -0.37 for levels of soluble stem pigment(s) (SSP). Absolute values of R between FE and CEE were 0.40 or greater in 40, 17, 33, 29, and 83% of all correlation analyses for DLA, LLM, MIF, LLO, and SSP, respectively. Spearman's coefficients of rank correlation (r s) between FE and CEE based on average performance were 0.55, -0.20, 0.40, 0.42, and -0.44 for DLA, LLM, MIF, LLO, and SSP, respectively. Disease development was slow when foliage was inoculated with a mycelial suspension. Based on experiment (E) by cultivar (C) interaction and rs values between replicate experiments within each method, determination of soluble stem pigment levels (0.86 ≤ rs ≤ 0.97; P < 0.001 for 100% of six analyses; P = 0.98 for E × C interaction) and measurement of lesion lengths on stems discolored by oxalic acid (0.27 ≤ rs ≤ 0.85; rs ≥ 0.58 and P ≤ 0.05 for 68% of 28 analyses; P = 0.07 for E × C interaction) were the most repeatable methods. The results from this study suggest that determination of levels of soluble pigments in stems, measurement of lesion lengths on stems discolored by oxalic acid, and the detached leaf assay may be better than mycelial inoculation of stems or foliage in evaluating soybean cultivars for field resistance to S. sclerotiorum.

Factors Associated with Prenatal Smoking Among Black Women in Eastern North Carolina

2005 ◽  
Vol 9 (3) ◽  
pp. 245-252 ◽  
Author(s):  
Suezanne T. Orr ◽  
Edward Newton ◽  
Patrick M. Tarwater ◽  
David Weismiller
Keyword(s):  
North Carolina ◽  
Black Women ◽  
Prenatal Smoking ◽  
Factors Associated ◽  
Eastern North Carolina

Sensitivity of Fusarium oxysporum f. sp. niveum to Prothioconazole and Pydiflumetofen In Vitro and Efficacy for Fusarium Wilt Management in Watermelon

2020 ◽  
Vol 21 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Nathan F. Miller ◽  
Jeffrey R. Standish ◽  
Lina M. Quesada-Ocampo
Keyword(s):  
North Carolina ◽  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Field Experiments ◽  
Foliar Application ◽  
Citrullus Lanatus ◽  
Disease Incidence ◽  
Application Rate ◽  
Current Evidence ◽  
Progress Curve

Field experiments were conducted in 2015 and 2016 to determine the effects of drench or drench-plus-foliar applications of prothioconazole and pydiflumetofen on Fusarium wilt (caused by Fusarium oxysporum f. sp. niveum; FON) of watermelon (Citrullus lanatus var. lanatus). In both years, all fungicide treatments reduced final disease incidence, final severity, and area under the disease progress curve, regardless of application rate or method. Yield data were collected in 2016, and both number and weight of marketable fruit were greatest in plots treated with pydiflumetofen as a drench-plus-foliar application at either application rate. Additional experiments were conducted to characterize sensitivity distributions of 48 isolates of FON from North Carolina to prothioconazole and pydiflumetofen. Mean prothioconazole EC50 values ranged from 0.10 to 0.55 µg/ml, and mean pydiflumetofen EC50 values ranged from 0.34 to 1.88 µg/ml. The results presented here validate pydiflumetofen as an effective management option for Fusarium wilt of watermelon, confirm previously observed efficacy of prothioconazole, and provide current evidence of pathogen sensitivity to these fungicides in North Carolina.

The Seasonal End of Human Coronavirus Hospital Admissions with Implications for SARS-CoV-2 (Preprint)

2020 ◽  
Author(s):  
Alan T Evangelista
Keyword(s):  
Hospital Admissions ◽  
Disease Incidence ◽  
Influenza Viruses ◽  
Seasonal Effects ◽  
Human Coronavirus ◽  
Enveloped Virus ◽  
Multiplex Pcr Assay ◽  
Contact Transmission ◽  
Human Coronaviruses

UNSTRUCTURED The seasonality of influenza viruses and endemic human coronaviruses was tracked over an 8-year period to assess key epidemiologic reduction points in disease incidence for an urban area in the northeast United States. Patients admitted to a pediatric hospital with worsening respiratory symptoms were tested using a multiplex PCR assay from nasopharyngeal swabs. The additive seasonal effects of outdoor temperatures and indoor relative humidity (RH) were evaluated. The 8-year average peak activity of human coronaviruses occurred in the first week of January, when droplet and contact transmission was enabled by the low indoor RH of 20-30%. Previous studies have shown that an increase in RH to 50% has been associated with markedly reduced viability and transmission of influenza virus and animal coronaviruses. As disease incidence was reduced by 50% in early March, to 75% in early April, to greater than 99% at the end of April, a relationship was observed from colder temperatures in January with a low indoor RH to a gradual increase in outdoor temperatures in April with an indoor RH of 45-50%. As a lipid-bound, enveloped virus with similar size characteristics to endemic human coronaviruses, SARS-CoV-2 should be subject to the same dynamics of reduced viability and transmission with increased humidity. In addition to the major role of social distancing, the transition from lower to higher indoor RH with increasing outdoor temperatures could have an additive effect on the decrease in SARS-CoV-2 cases in May. Over the 8-year period of this study, human coronavirus activity was either zero or >99% reduction in the months of June through September, and the implication would be that SARS-Cov-2 may follow a similar pattern. INTERNATIONAL REGISTERED REPORT RR2-doi.org/10.1101/2020.05.15.20103416

Factors associated with the development of paediatric chronic otitis media by age nine: a prospective longitudinal cohort study of 6560 children

2020 ◽  
pp. 1-12
Author(s):  
P J Clamp ◽  
K De-Loyde ◽  
A R Maw ◽  
S Gregory ◽  
J Golding ◽  
...  
Keyword(s):  
Cohort Study ◽  
Otitis Media ◽  
Maternal Education ◽  
Univariate Analysis ◽  
Chronic Otitis Media ◽  
Birth Cohort Study ◽  
Control Group ◽  
Factors Associated ◽  
Prospective Longitudinal

Abstract Objective This study aimed to analyse social, health and environmental factors associated with the development of chronic otitis media by age nine. Method This was a prospective, longitudinal, birth cohort study of 6560 children, reviewed at age nine. Chronic otitis media defined as previous surgical history or video-otoscopic changes of tympanic membrane retraction, perforation or cholesteatoma. Non-affected children were used as the control group. Results Univariate analysis demonstrated an association between chronic otitis media and otorrhoea, snoring, grommet insertion, adenoidectomy, tonsillectomy, hearing loss, abnormal tympanograms and preterm birth. Multivariate analysis suggests many of these factors may be interrelated. Conclusion The association between chronic otitis media and otorrhoea, abnormal tympanograms and grommets supports the role of the Eustachian tube and otitis media (with effusion or acute) in the pathogenesis of chronic otitis media. The role of snoring, adenoidectomy and tonsillectomy is unclear. Associations suggested by previous studies (sex, socioeconomic group, parental smoking, maternal education, childcare, crowding and siblings) were not found to be significant predictors in this analysis.

scholarly journals Periodic limb movements in patients with obstructive sleep apnea syndrome

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiaobo Zhou ◽  
Bo Zhou ◽  
Zhe Li ◽  
Qiao Lu ◽  
Shaoping Li ◽  
...  
Keyword(s):  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Obstructive Sleep Apnea Syndrome ◽  
Sleep Apnea Syndrome ◽  
Periodic Limb Movements ◽  
Limb Movements ◽  
Factors Associated ◽  
Obstructive Sleep ◽  
Apnea Syndrome

AbstractThe aim of the study was to assess the factors associated with periodic limb movements during sleep (PLMS) among obstructive sleep apnea syndrome (OSAS) patients and identify the role of PLMS in patients with OSAS. 303 adult patients with OSAS were included in the study. All patients completed physical examination, Epworth sleepiness scale (ESS), and polysomnography. Diagnosis of PLMS was made if the periodic leg movements index (PLMI) was ≥ 15. Chi-square test, ANOVA, univariate and multivariate logistic regression analyses were conducted to identify factors associated with PLMS among OSAS patients. Statistical analyses were performed with SPSS 26.0 for mac. Statistically significant difference was considered if P value < 0 .05. Among the 303 adult patients with OSAS, 98 patients had significant PLMS and the other 205 had no significant PLMS. Compared with OSAS patients without PLMS, OSAS patient with PLMS were older, had shorter REM duration and greater apnea–hypopnea index (AHI) (P < 0.05). The study suggests that PLMS is a matter of concern among patients with OSAS. A better understanding of the role of PLMS among OSAS patients could be useful in better recognition, intervention and treatment of OSAS.

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