scholarly journals Investigation on the Severity of Alternaria Blight of Pigeonpea and its Characterisation in Northern Karnataka

Author(s):  
A.S. Savitha ◽  
K. Ajithkumar ◽  
S.T. Yenjerappa

Background: The Alternaria blight of pigeonpea is considered as an important foliar disease and poses threat to the pigeonpea cultivation due to change in the climatic condition, cultivation practices and variation in pathogenic character. Though the disease is noticed in an alarming proportion after the post rainy season and causing economic yield, little is known about the severity of disease and its impact on crop production. The current study is aimed to study the disease severity and variability of the pathogen and which would helps us to understand the biology of the pathogen to develop suitable management strategies. Methods: In the field and laboratory investigations during 2015 and 2017, different localities of Northern Karnataka were surveyed. Twenty sampling localities were selected based on geographical situation. In the laboratory, collected diseased samples were isolated and determined morphologically and culturally based on taxonomic and molecular characters. Result: Our investigations revealed the varied disease severity in surveyed districts, Vijayapura district recorded the maximum disease severity with a range of 38.67 to 49.33 and this might be due to variation in pathogenic character, rainfall pattern and climatic conditions and also disease severity varied with varieties indicating the source of resistance. The present study contributed for identification of geographical distribution of the disease and its severity in different varieties and places of Northern Karnataka and their genetic and morphological variations.

Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 548 ◽  
Author(s):  
Panagiotis Kanatas ◽  
Ilias S. Travlos ◽  
Ioannis Gazoulis ◽  
Alexandros Tataridas ◽  
Anastasia Tsekoura ◽  
...  

Decision support systems (DSS) have the potential to support farmers to make the right decisions in weed management. DSSs can select the appropriate herbicides for a given field and suggest the minimum dose rates for an herbicide application that can result in optimum weed control. Given that the adoption of DSSs may lead to decreased herbicide inputs in crop production, their potential for creating eco-friendly and profitable weed management strategies is obvious and desirable for the re-designing of farming systems on a more sustainable basis. Nevertheless, it is difficult to stimulate farmers to use DSSs as it has been noticed that farmers have different expectations of decision-making tools depending on their farming styles and usual practices. The function of DSSs requires accurate assessments of weeds within a field as input data; however, capturing the data can be problematic. The development of future DSSs should target to enhance weed management tactics which are less reliant on herbicides. DSSs should also provide information regarding weed seedbank dynamics in the soil in order to suggest management options not only within a single period but also in a rotational view. More aspects ought to be taken into account and further research is needed in order to optimize the practical use of DSSs for supporting farmers regarding weed management issues in various crops and under various soil and climatic conditions.


2006 ◽  
Vol 31 (4) ◽  
pp. 337-341 ◽  
Author(s):  
Ricardo Braga Baldassari ◽  
Renato Ferrari Reis ◽  
Antonio de Goes

The importance of the presence of symptomatic fruits with citrus black symptoms (CBS) on the disease severity level in subsequent crop production was assessed in an orchard planted with Valência and Natal sweet orange varieties. Additionally, the period of susceptibility of the fruits of these varieties was evaluated. Fruits were covered with paper bags at the stage of 75% fallen petals and were then exposed to natural infection at weekly intervals, from October 2000 to April 2001. This process was carried out in plants where the fruits from the previous harvest had been picked as well as in plants where fruits remained until natural drop. The evaluation of disease severity used a scale that varied from 0 (absence of symptoms) to 6 (severe symptoms). It was observed that, for the Valência and Natal varieties, conidia of Phyllosticta citricarpa that had formed on the lesions of fruits from the previous harvest did not significantly increase the severity of disease on the fruits of the subsequent harvest period. In this study, the protection of the fruits until 10 weeks after petal drop did not affect the number of lesions, indicating that ascospore discharges after that date were, probably, responsible for disease severity. Fruits exposed between the 20th and 24th week after 75% of the petals had fallen were symptomatic, indicating that, at this stage, the fruits were still susceptible to the pathogen.


2018 ◽  
Vol 5 (03) ◽  
Author(s):  
HK SINGH ◽  
SUDHAKAR SHUKLA ◽  
JAY KUMAR YADAV ◽  
MANISH KUMAR MAURYA ◽  
KN MAURYA

Alternaria blight is destructive disease of rapeseed- mustard caused by Alternaria brassicae (Berk) Sacc. and A. brassicicola (Schw). The field experiments were conducted during 2013-14 and 2014-15, with 200 genotypes for evaluation of their resistance to Alternaria blight, as well as to develop effective management strategies for this disease. None of the genotypes were found disease free or highly resistant, only 7 genotypes namely (DLSC-1, DRMR-261, DRMR-270, GSC-101, GSL-1, NPC-20 and PHR-2) were found resistant, 15 genotypes were rated as moderately resistant. Rest of the genotypes was either recorded susceptible or highly susceptible.For disease management, newly molecules of 6 fungicides were evaluated with 13 treatments combinations for their effectiveness. Propiconazole 25% EC @ 0.10% was found most effective in reducing the disease severity followed by same fungicide @ 0.05%. It was followed by Hexaconazole 5% SC @ 0.010%. Maximum test weight and yield was also recorded with the sprays of Propiconazole 25% EC @ 0.10% followed by same fungicide @ 0.05%. In comparison to other fungicides, the maximum B:C ratio was recorded with three sprays of Hexaconazole 5% SC @ 0.05% followed by Propiconazole 25% EC @ 0.05%.


2021 ◽  
Vol 10 (5) ◽  
pp. 309
Author(s):  
Zixu Wang ◽  
Chenwei Nie ◽  
Hongwu Wang ◽  
Yong Ao ◽  
Xiuliang Jin ◽  
...  

Maize (Zea mays L.), one of the most important agricultural crops in the world, which can be devastated by lodging, which can strike maize during its growing season. Maize lodging affects not only the yield but also the quality of its kernels. The identification of lodging is helpful to evaluate losses due to natural disasters, to screen lodging-resistant crop varieties, and to optimize field-management strategies. The accurate detection of crop lodging is inseparable from the accurate determination of the degree of lodging, which helps improve field management in the crop-production process. An approach was developed that fuses supervised and object-oriented classifications on spectrum, texture, and canopy structure data to determine the degree of lodging with high precision. The results showed that, combined with the original image, the change of the digital surface model, and texture features, the overall accuracy of the object-oriented classification method using random forest classifier was the best, which was 86.96% (kappa coefficient was 0.79). The best pixel-level supervised classification of the degree of maize lodging was 78.26% (kappa coefficient was 0.6). Based on the spatial distribution of degree of lodging as a function of crop variety, sowing date, densities, and different nitrogen treatments, this work determines how feature factors affect the degree of lodging. These results allow us to rapidly determine the degree of lodging of field maize, determine the optimal sowing date, optimal density and optimal fertilization method in field production.


Author(s):  
Marianna Fenzi ◽  
Paul Rogé ◽  
Angel Cruz-Estrada ◽  
John Tuxill ◽  
Devra Jarvis

AbstractLocal seed systems remain the fundamental source of seeds for many crops in developing countries. Climate resilience for small holder farmers continues to depend largely on locally available seeds of traditional crop varieties. High rainfall events can have as significant an impact on crop production as increased temperatures and drought. This article analyzes the dynamics of maize diversity over 3 years in a farming community of Yucatán state, Mexico, where elevated levels of precipitation forced farmers in 2012 to reduce maize diversity in their plots. We study how farmers maintained their agroecosystem resilience through seed networks, examining the drivers influencing maize diversity and seed provisioning in the year preceding and following the 2012 climatic disturbance (2011–2013). We found that, under these challenging circumstances, farmers focused their efforts on their most reliable landraces, disregarding hybrids. We show that farmers were able to recover and restore the diversity usually cultivated in the community in the year following the critical climate event. The maize dynamic assessed in this study demonstrates the importance of community level conservation of crop diversity. Understanding farmer management strategies of agrobiodiversity, especially during a challenging climatic period, is necessary to promote a more tailored response to climate change in traditional farming systems.


Plant Disease ◽  
2010 ◽  
Vol 94 (3) ◽  
pp. 339-344 ◽  
Author(s):  
A. Suthaparan ◽  
Arne Stensvand ◽  
S. Torre ◽  
Maria L. Herrero ◽  
R. I. Pettersen ◽  
...  

The effect of day length on production and germinability of conidia and severity of disease caused by Podosphaera pannosa, the causal agent of rose powdery mildew, was studied. Whole potted plants or detached leaves of Rosa interspecific hybrid ‘Mistral’ were inoculated with P. pannosa and exposed to 0, 12, 18, 20, 22, or 24 h of artificial light per day in growth chambers equipped with mercury lamps. Increasing duration of illumination from 18 to 20 to 24 h per day reduced production of conidia by 22 to 62%. Exposure to 24 h of illumination per day also strongly reduced disease severity compared with 18 h. Our results suggest that increasing day lengths from 18 h per day to 20 to 24 h may suppress the disease significantly and, thereby, reduce the need for fungicide applications against powdery mildew.


2020 ◽  
Vol 13 (1) ◽  
pp. 144
Author(s):  
Dianxi Zhang ◽  
Muhammad Safdar Sial ◽  
Naveed Ahmad ◽  
António José Filipe ◽  
Phung Anh Thu ◽  
...  

Water scarcity is rising as a global issue, because the planet earth is facing a global water crisis, which is considered something that can destroy environmental sustainability of our planet. The fact is that humanity’s demand is depleting natural resources faster than nature can replenish itself; if human habits and unsustainable use of water resources do not change, water scarcity will inevitably intensify and become a major cause of conflict among different nations of the world. The water scarcity issue is a crucial issue but unfortunately it has not received due attention in past. Pakistan, which once was a water abundant country, now facing a situation of water scarcity. Pakistan has a poor irrigation system which results 60% loss of its water; Pakistan uses more water for crop production than other countries. Likewise, the country harvests water from rainfall, rivers, snow, and glaciers. The country is facing a serious water crisis that is caused by different factors, such as changing climatic conditions, rising population, poor irrigation system, poor political will, and rapid urbanization. The water crisis of Pakistan is expected to worsen in coming years. This is a drastic situation which calls for emergency measures. With this background, the present study provides a detailed view of the water situation in the country with challenges to water management. The study also suggests some recommendations for policymakers to improve the water crisis situation in the future.


2021 ◽  
Vol 50 (1) ◽  
pp. 15-19
Author(s):  
Rakesh Punia ◽  
Pavitra Kumari ◽  
Anil Kumar ◽  
AS Rathi ◽  
Ram Avtar

Progression of Alternaria blight disease was measured on two susceptible Indian mustard varieties viz., RH 30 and RH 0749 sown at three different dates. The maximum increase in disease severity was recorded between first weeks of February and last week of February. During this period, the maximum and minimum temperature, relative humidity at morning and evening, average vapour pressure of morning and evening, maximum and bright sunshine hours and wind speed were higher, which resulted in congenial conditions for severe infection by the pathogen. The disease severity was positively correlated with maximum and minimum temperature, average vapour pressure, wind speed, sunshine hours and evaporation, while relative humidity and rainfall negatively correlated with Alternaria blight on both the varieties. A maximum value of area under disease progress curve was observed on cultivar RH 30 (651.1 cm2) as compared to RH 0749 (578.9 cm2), when crop was sown on 9th November.


2020 ◽  
Author(s):  
Shan Cao ◽  
Lulu Sun ◽  
Zhongxiang Shi ◽  
Baoqi Yang ◽  
Furen Zhang

Abstract Background: Pemphigus and bullous pemphigoid (BP) are autoimmune blistering diseases (AIBDs) that affect the skin and mucous membranes, and adversely impact quality of life (QOL). Few studies have assessed the correlation between the severity of disease and QOL in patients with pemphigus and BP. Objectives: To identify the correlation between the severity of AIBDs and QOL using the Autoimmune Bullous Disease Quality of Life (ABQOL), Treatment Autoimmune Bullous Disease Quality of Life (TABQOL), and Dermatology Life Quality Index (DLQI) questionnaires in Chinese patients with pemphigus and BP at baseline, and after 1, 3 and 6 months of treatment. Methods: Pemphigus and BP patients were invited to complete the ABQOL, TABQOL, and DLQI questionnaires. We measured the pemphigus disease area index (PDAI), autoimmune bullous skin disorder intensity score (ABSIS), and antibodies of desmoglein1,desmoglein3 (DSG1/DSG3) for pemphigus; and the bullous pemphigoid disease area index (BPDAI), ABSIS, and antibodies of BP180/ BP230 for BP as disease severity indices. The correlations between the severity of disease and QOL were analyzed by Spearman’s correlation coefficient (r). Results: Eighty-five patients were included: 55 with pemphigus and 30 with BP. The pemphigus subtypes included pemphigus vulgaris (PV, n = 32), pemphigus foliaceus (PF, n = 22), and paraneoplastic pemphigus (PNP, n = 1). We found significantly strong correlations between QOL (ABQOL, TABQOL, DLQI) and severity of disease (PDAI/BPDAI, ABSIS) with (r = 0.87, 0.77, 0.83; r = 0.86, 0.73, 0.80) for pemphigus and BP, respectively. Mild or strong correlations were also observed between QOL and antibody titers in pemphigus with DSG1/DSG3(r=0.32/0.36) and BP with BP180/BP230( r = 0.73/0.17) respectively. Conclusion: The QOL of patients with pemphigus and BP decreased with increased severity of the AIBDs. As the disease severity descended, so the QOL improved. The QOL indices should be used in clinical trials and to manage patients’ treatment, especially during the active disease stage, despite the mild correlation observed after 1 month of treatment.The PDAI to be better at assessing disease severity than the ABSIS in patients with pemphigus, and ABSIS are better than BPDAI in BP patients for correlation with the QOL indices.


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