Epidemiology and control of spot form of net blotch (Pyrenophora teres f. maculata) of barley: a review

2009 ◽  
Vol 60 (4) ◽  
pp. 303 ◽  
Author(s):  
Mark S. McLean ◽  
Barbara J. Howlett ◽  
Grant J. Hollaway

Spot form of net blotch (SFNB), caused by the fungus Pyrenophora teres f. maculata, was first described in Denmark in the 1960s and is now a prevalent foliar disease of barley in many countries. This disease should be controlled as a separate disease-causing organism from the net form of net blotch (NFNB), which is caused by P. teres f. teres. The increase in prevalence of SFNB is primarily due to stubble retention and cultivation of susceptible varieties, which have resulted in increased inoculum. Infected barley stubble is the primary inoculum source for SFNB, producing both asexual spores (conidia) and sexual spores (ascospores) from pseudothecia. Spot form of net blotch causes significant losses in grain yield and quality in situations where inoculum is present, susceptible varieties are cultivated, and where the climate is cool and moist. Cultivation of resistant varieties is the most cost-effective method for control of SFNB and more than 12 different resistance sources have been identified in barley germplasm and wild barley relatives. The resistance loci of 11 of these have been mapped. Control of SFNB can also be achieved with application of foliar fungicides, crop rotation, and stubble destruction.

2009 ◽  
Vol 60 (5) ◽  
pp. 499 ◽  
Author(s):  
Mark S. McLean ◽  
Barbara J. Howlett ◽  
Grant J. Hollaway

Spot form of net blotch (SFNB), caused by the fungus Pyrenophora teres f. maculata, was first described in Denmark in the 1960s and is now a prevalent foliar disease of barley in many countries. This disease should be controlled as a separate disease-causing organism from the net form of net blotch (NFNB), which is caused by P. teres f. teres. The increase in prevalence of SFNB is primarily due to stubble retention and cultivation of susceptible varieties, which have resulted in increased inoculum. Infected barley stubble is the primary inoculum source for SFNB, producing both asexual spores (conidia) and sexual spores (ascospores) from pseudothecia. Spot form of net blotch causes significant losses in grain yield and quality in situations where inoculum is present, susceptible varieties are cultivated, and where the climate is cool and moist. Cultivation of resistant varieties is the most cost-effective method for control of SFNB and more than 12 different resistance sources have been identified in barley germplasm and wild barley relatives. The resistance loci of 11 of these have been mapped. Control of SFNB can also be achieved with application of foliar fungicides, crop rotation, and stubble destruction.


1965 ◽  
Vol 45 (2) ◽  
pp. 189-193 ◽  
Author(s):  
K. W. Buchannon ◽  
W. C. McDonald

The reaction to infection by Pyrenophora teres Drechs., the incitant of net blotch of barley, was determined for 6,174 varieties in the U.S.D.A. World Barley Collection. Forty varieties, seventeen of them from Ethiopia, were resistant in the seedling stage to a highly pathogenic strain of the fungus prevalent in Western Canada and to composites of isolates from Manitoba, Saskatchewan, Alberta, Ontario, North Dakota, California, and Mexico. They were also resistant in the field at three locations in Western Canada. Agronomic and malting quality characteristics for the resistant varieties were also recorded.


1966 ◽  
Vol 6 (23) ◽  
pp. 437 ◽  
Author(s):  
WA Shipton

The influence of a natural infection of net blotch, caused by Pyrenophora teres Dreschl., on the yield and quality of Beecher barley was determined. The disease was controlled in some of the experimental plots by spraying with fungicides at regular intervals. The highest yield (51.9 bushels per acre) and the lowest leaf infection score (24 per cent of the maximum value) were on plots sprayed with Manganous ethylene bisdithiocarbamate (Maneb). By contrast the yield on the unsprayed plots was 17.4 per cent lower and the leaf infection score 28 per cent higher. Bushel and kernel weights were depressed by infection and the proportion of small grains increased. Grain from plots sprayed with Maneb yielded 2.8 per cent more extract of malt than grain from the control plots. The nitrogen content of the grain was not significantly affected, and the saccharification rate was similar for all treatments.


2020 ◽  
Vol 13 (5) ◽  
Author(s):  
Saeid Amanloo ◽  
Farzad Katiraee ◽  
​Zahra ​Jahanshiri ◽  
Mojtaba Didehdar ◽  
Jamshid Mohammadi ◽  
...  

Background: Candida albicanss has been introduced as one of the most common causes of nosocomial infections. Molecular typing methods are powerful tools in epidemiology to investigate the infection source of candidiasis, identify the transmission routes, and control the measures. Objectives: This study aimed for genotyping C. albicans species isolated from oral cavities of the non-HIV patients who suffer from oropharyngeal candidiasis via combined ABC and repeat sequences (RPS) typing systems. Methods: In this study, 31 DNA samples of clinical isolates of C. albicans were evaluated in terms of 25s ribosomal DNA region sequence or ABC typing, and ALT repeats numbers within RPS. DNA was amplified in two separate reactions, and the PCR products were electrophoresed to identify the genotypes of the isolates. Based on the band's pattern, phylogenetic analysis was conducted by UPGMA, and the discriminatory power of ABC and RPS typing was measured by Simpson’s index of diversity. Results: Genotype A with (14 isolates, 45.2%) were the most frequent and followed by genotype B (10 isolates, 32.3%) and Genotype C (7 isolates, 22.6%), respectively. In addition, genotype 3 with 25 isolates (80.6%) were the most prevalent, followed by genotype 2/3 (4 isolates, 12.9%) and genotype 3/4 (2 isolates, 6.5%) respectively. No significant relationship was found between the obtained genotypes and drug-resistant isolates (P < 0.05). Conclusions: This study showed that 25s rDNA and RPS typing is a quick, simple, and cost-effective method with average discriminatory power and good reproducibility for C. albicans genotyping. It can be used for the epidemiology of C. albicans infections.


The choice of cost-effective method of anticorrosive protection of steel structures is an urgent and time consuming task, considering the significant number of protection ways, differing from each other in the complex of technological, physical, chemical and economic characteristics. To reduce the complexity of solving this problem, the author proposes a computational tool that can be considered as a subsystem of computer-aided design and used at the stage of variant and detailed design of steel structures. As a criterion of the effectiveness of the anti-corrosion protection method, the cost of the protective coating during the service life is accepted. The analysis of existing methods of steel protection against corrosion is performed, the possibility of their use for the protection of the most common steel structures is established, as well as the estimated period of effective operation of the coating. The developed computational tool makes it possible to choose the best method of protection of steel structures against corrosion, taking into account the operating conditions of the protected structure and the possibility of using a protective coating.


2020 ◽  
Vol 2020 (3) ◽  
pp. 60408-1-60408-10
Author(s):  
Kenly Maldonado ◽  
Steve Simske

The principal objective of this research is to create a system that is quickly deployable, scalable, adaptable, and intelligent and provides cost-effective surveillance, both locally and globally. The intelligent surveillance system should be capable of rapid implementation to track (monitor) sensitive materials, i.e., radioactive or weapons stockpiles and person(s) within rooms, buildings, and/or areas in order to predict potential incidents proactively (versus reactively) through intelligence, locally and globally. The system will incorporate a combination of electronic systems that include commercial and modifiable off-the-shelf microcomputers to create a microcomputer cluster which acts as a mini supercomputer which leverages real-time data feed if a potential threat is present. Through programming, software, and intelligence (artificial intelligence, machine learning, and neural networks), the system should be capable of monitoring, tracking, and warning (communicating) the system observer operations (command and control) within a few minutes when sensitive materials are at potential risk for loss. The potential customer is government agencies looking to control sensitive materials and/or items in developing world markets intelligently, economically, and quickly.


2020 ◽  
Vol 11 (SPL1) ◽  
pp. 716-722
Author(s):  
Sneha Dhakite ◽  
Sadhana Misar Wajpeyi

The “Coronavirus disease 19 (COVID-19)” is caused by “Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)”, a newly discovered member of the Coronaviridae family of viruses which is a highly communicable. There is no effective medical treatment till date for Coronavirus disease hence prevention is the best way to keep disease away. Rasayana proved to be highly efficacious and cost effective for the Prevention and Control of viral infections when vaccines and standard therapies are lacking. Rasayana Chikitsa is one of the eight branches of Ashtanga Ayurveda which helps to maintain healthy life style. Rasayana improves immunity and performs many vital functions of human body. Vyadhikshamatva that is immune mechanism of the body is involved in Prevention of the occurrence of a new disease and it also decreases the virulence and progression of an existing disease. In COVID-19 the Respiratory system mainly get affected which is evident from its symptoms like cold, cough and breathlessness. Here the drugs help in enhancing immune system and strengthening functions of Respiratory system can be useful. For this purpose, the Rasayana like Chyavanprasha, Agastya Haritaki, Pippali Rasayana, Guduchi, Yashtimadhu, Haridra, Ashwagandha, Tulsi are used. Rasayana working on Respiratory system are best for Prevention of Coronavirus and boosting immune system. Rasayana Chikitsa can be effective in the Prevention as well as reducing symptoms of COVID-19.


2020 ◽  
Author(s):  
Jagjit S Soar

he current COVID-19 pandemic now believed to be based on the mutation of the SARS-CoV virus (first reported in 2002) to SARS-CoV-2 emerging in 2019, is naturally causing extreme worry and concern around the world with sometimes mixed and incoherent messages on how to deal with it. There is a plethora of information from previous epidemics caused by other coronaviruses such as severe acute respiratory syndrome, SARS (2002) and Middle East respiratory syndrome MERS (2012) from which we can extrapolate guidance on how to deal with the current pandemic. In the current absence of specific pharmaceutical agents, we propose assessing the extended tools that we already possess in our biological armoury to combat, prevent and control the spread of this virus. Using a set of precise criteria to locate such possible contenders, we conducted literature searches to find compounds that met these criteria. We have now reduced this to a shortlist of three agents that may be the best candidates. We propose vitamin C, vitamin D and Curcumin fit our criteria well. These compounds are widely available to the general public. They are available online and over-the-counter as supplements. Otherwise healthy individuals are safely able to self-administer these agents as a prophylactic to protect themselves and to enhance their immune response. This would be especially desirable for the elderly and at risk groups. These agents can also be used as adjunct therapy, particularly for those who may have early symptoms. This preventative therapy could be implemented whilst awaiting specific pharmaceutical drugs to emerge as a treatment for COVID-19. Our suggested compounds are a highly cost-effective way to potentially reduce the mortality that is regretfully mounting as a result of COVID-19 infection. The biological mode of action and the dosing of these compounds are summarised.


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