STUDIES ON THE SEEDLING DISEASE OF BARLEY CAUSED BY HELMINTHOSPORIUM SATIVUM P.K. & B.

1956 ◽  
Vol 34 (4) ◽  
pp. 653-673 ◽  
Author(s):  
R. A. Ludwig ◽  
R. V. Clark ◽  
J. B. Julien ◽  
D. B. Robinson
Keyword(s):  
Disease Incidence ◽  
Infested Soil ◽  
Disease Development ◽  
Toxic Activity ◽  
Factors Affecting ◽  
Seedling Disease ◽  
Nutrient Salt ◽  
Helminthosporium Sativum ◽  
Treatment Comparisons

A standard sand – cornmeal – nutrient salt medium, for use in the production of artificial inoculum of Helminthosporium sativum, is described. This inoculum induces uniform plant disease development when thoroughly incorporated with the planting soil. The results presented clearly demonstrate the necessity of using a series of infestation levels in studies of factors affecting disease development in artificially infested soil. It is shown that considerable reliance can be placed on treatment comparisons within an experiment but that comparisons between experiments are much less accurate. The role of a toxin (or toxins) in disease development in barley seedlings has been demonstrated. The toxic activity was found to be distinct from that frequently encountered on addition of organic matter to soil. Results obtained suggest that toxin adsorption by the soil may play an important role in reducing disease incidence and severity.

Some factors affecting the development and biocontrol of cotton seedling disease

1995 ◽  
Vol 35 (6) ◽  
pp. 771 ◽  
Author(s):  
HJ Ogle ◽  
AM Stirling ◽  
PJ Dart
Keyword(s):  
Pythium Ultimum ◽  
Disease Development ◽  
Symptom Development ◽  
Night Temperature ◽  
Factors Affecting ◽  
Seedling Disease ◽  
Susceptibility To Infection ◽  
Temperature Regimes ◽  
Effects Of Temperature ◽  
Number Of Seeds

The effects of temperature and cultivar on disease development in cotton were investigated in addition to the duration of susceptibility to infection and the timing of infection by Pythium ultimum and Rhizoctonia solani. Symptom development was also monitored. Disease was more severe at day/night temperature regimes of 20/15, 25/20, and 30/25�C than at 35/30�C. Disease development differed significantly between cotton cvv. Deltapine 90 and Siokra 1-4 at 30/25�C and 35/30�C. In glasshouse trials in field soil, both R. solani and P ultimum were isolated from seeds as early as 2 h after inoculation, although most seeds were not infected with P. ultimum until 10 h after inoculation and with R. solani until 24 h after inoculation. Increasing the duration of exposure to inoculum increased the number of seeds infected and reduced the number of plants surviving. Seedlings were resistant to P. ultimum infection by 14 days after sowing but were not resistant to infection by R. solani until 28 days after sowing.

scholarly journals Factors Affecting Concentrations of Airborne Conidia of Oidium sp. Among Poinsettias in a Greenhouse

Plant Disease ◽  
2000 ◽  
Vol 84 (10) ◽  
pp. 1089-1095 ◽  
Author(s):  
J. M. Byrne ◽  
M. K. Hausbeck ◽  
B. D. Shaw
Keyword(s):  
Relative Humidity ◽  
Rapid Decrease ◽  
Disease Development ◽  
Factors Affecting ◽  
Influence Of Temperature ◽  
Large Numbers ◽  
Airborne Conidia ◽  
Influence Of Temperature On ◽  
Atmospheric Concentrations

Atmospheric concentrations of Oidium sp. conidia in two research greenhouses containing infected poinsettias were monitored to investigate the role of environment in prompting conidial release and dissemination. Hourly concentrations of conidia of Oidium sp. were estimated using a Burkard volumetric spore sampler. The influence of temperature on disease development was studied by placing healthy poinsettias in each greenhouse for 7-day periods, removing them, and recording the days to the appearance of the first colony. When averaged over 5 December to 1 June, atmospheric conidial concentrations in greenhouse (GH) 2 were greatest during 1000 to 1800 hours with a peak (325 conidia/m3/h) occurring at 1200 hours. In GH 11, peak concentrations occurred at 1300 hours (65 conidia/m3/h) and 1600 hours (75 conidia/m3/h). Large numbers of conidia were sampled (≥100/m3) within 1-h periods, indicating conidial release events (CREs). Fluctuations in relative humidity (RH) (either positive or negative) prompted CREs. In both greenhouses, the highest number of CREs (up to 23) occurred following RH fluctuations of 5 to 15%. Watering resulted in an immediate increase (≤25%) followed by a rapid decrease in RH (≤32%) beginning 1 to 2 h later. In GH 2 and GH 11, 89 and 48%, respectively, of the CREs occurred within 3 h following greenhouse watering. When greenhouse temperatures exceeded 25°C for 21 days in May (GH 2) and 19 days in March (GH 11), atmospheric conidial concentrations were reduced 80 and 75% from the previous months, respectively.

scholarly journals Role of some Factors Affecting Crown Gall Disease Development

2011 ◽  
Vol 39 (1) ◽  
pp. 89-108
Author(s):  
Farouk Barakat ◽  
Maurice Mikhail ◽  
Aly Tawfik ◽  
Rabab Abd-El-Aziz
Keyword(s):  
Crown Gall ◽  
Disease Development ◽  
Factors Affecting ◽  
Crown Gall Disease

EFFECT OF INSECTICIDES AND HERBICIDES APPLIED TO SOIL ON THE DEVELOPMENT OF PLANT DISEASES. I. THE SEEDLING DISEASE OF BARLEY CAUSED BY HELMINTHOSPORIUM SATIVUM P. K. & B.

1957 ◽  
Vol 37 (3) ◽  
pp. 196-204 ◽  
Author(s):  
Lloyd T. Richardson
Keyword(s):  
Plant Diseases ◽  
Disease Development ◽  
Infection Group ◽  
Seedling Disease ◽  
Helminthosporium Sativum ◽  
Group A ◽  
Group B ◽  
Group D ◽  
Development Group ◽  
Growth Of Seedlings

From the results obtained when nine insecticides and ten herbicides were applied at a series of dosages to soil infested to various degrees with Helminthosporium sativum P.K. & B. it was found possible to separate these chemicals into four groups on the basis of their effects on the growth of barley seedlings and on the development of rootrot infection. Group A (schradan, isodrin, DCU, IPX, and TCA) affected neither host nor disease development. Group B (lindane, dieldrin, and DDT) stimulated the growth of barley seedlings without affecting disease development. Group C (maleic hydrazide and heptachlor) stimulated seedling growth but increased the severity of infection. Group D (aldrin, endrin, chlordane, NPA, 2,4-D, monuron, DNBP, and dalapon) did not affect the growth of seedlings but reduced rootrot infection. Only DNBP was toxic to H. sativum in culture.

Researching the factors influencing the satisfaction of master students at VNU School of Interdisciplinary Studies

2019 ◽  
Vol 35 (3) ◽  
Author(s):  
Do Huy Thuong ◽  
Nguyen Thi Phuong Hong
Keyword(s):  
Service Industry ◽  
Interdisciplinary Studies ◽  
Number Of Solutions ◽  
Factors Affecting ◽  
Training Institutions ◽  
Market Needs ◽  
Market Strategies ◽  
Students Satisfaction ◽  
Training Service

Improving the quality in order to keep up with the trend in the world is the vital task of training institutions today. Training institutions need to grasp market needs and satisfy the requirements of customers - learners. Nadiri, H., Kandampully, J & Hussain, K. (2009) argue that the managers in education need to apply market strategies that are being used by manufacturing and business enterprises and need to be aware that the role of training institutions is a service industry which is responsible for satisfying learner needs (Elliott & Shin, 2002). Currently, there have been many researches on students’ satisfaction. However, each research has its own objectives and is conducted on different scales. This study is implemented to provide information about the factors affecting master students’ satisfaction with the training service at VNU School of Interdisciplinary Studies (VNU SIS). Through it, the research offers a number of solutions to improving the satisfaction level of the master students at VNU SIS in the coming time.

Business Aviation in Russia: Specific Features and Prospects of Development

2020 ◽  
Vol 26 (1) ◽  
pp. 86-93
Author(s):  
D. V. Slivinsky ◽  
I. A. Fomina ◽  
D. G. Menshikh
Keyword(s):  
Systems Approach ◽  
National Policy ◽  
Civil Aviation ◽  
Economic Growth Rate ◽  
Factors Affecting ◽  
Organization And Management ◽  
Transport Services ◽  
Business Aviation ◽  
Wide Range

The presented study determines the role of business aviation in the modern economy and examines the specific features of its development in Russia.Aim. The study aims to analyze the development of business aviation in Russia and its correlation with economic development in general.Tasks. The authors determine the benefits of business aviation as a business tool, examine the specific features of the Russian business aviation market and problems of its development, and identify factors that affect the development of business aviation in Russia.Methods. This study uses the methods of comparative and retrospective analysis, cross-country comparison, systems approach, and expert analytics.Results. Business aviation is a new segment of civil aviation for Russia. Therefore, it is advisable to rely on foreign practices in the management of its development. In many countries, business aviation is a separate industry that specializes in providing transport services to a wide range of corporate clients and/or individuals. The development of this industry is associated with the economic growth rate and the development level of the national economy, and also depends on the national institutional specifics. This study describes the specific features of development of business aviation in Russia and problems arising in the organization and management of this type of business.Conclusions. The authors develop a system of factors affecting the development of business aviation in Russia, describe the major problems of this industry, and propose solutions. The results of this study can be used in the development (adjustment) of business aviation development strategies in Russia both at the industrial and corporate level, and in the implementation of the national policy in this field.

The methodology of experimental research of the feed components extrusion process in order to improve its energy performance

2020 ◽  
pp. 147-152
Author(s):  
E. M. Ratnikov ◽  
D. O. Milko
Keyword(s):  
Experimental Studies ◽  
Energy Performance ◽  
Extrusion Process ◽  
Mathematical Methods ◽  
Screw Extruder ◽  
Mathematical Planning ◽  
Factors Affecting ◽  
Extrusion Processing ◽  
Definition Of

Annotation Purpose. Development of a program and methods for conducting experimental studies of the extrusion process with the definition of parameters and modes of operation of the extruder to improve its energy performance. Methods. Methods of mathematical statistics, synthesis, analysis, description and modeling were used. Results. The application of mathematical methods, in particular mathematical planning, reduces the number of experiments several times, and allows to evaluate the role of influencing factors, obtain a mathematical model of the process and determine the optimal conditions for its parameters and modes, etc. Conclusions. The methodology for experimental studies of a screw extruder is presented with the necessary equipment and methodology for processing the obtained experimental data. A mathematical method of planning, which reduces the number of experiments several times, allows us to evaluate the role of factors affecting productivity and energy intensity is presented. Keywords: extruder, auger, nutrients, research methodology, extrusion, processing, feed.

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

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