Screening of genotypes against Alternaria blight of rapeseed-mustard and its fungicidal management

2018 ◽  
Vol 5 (03) ◽  
Author(s):  
HK SINGH ◽  
SUDHAKAR SHUKLA ◽  
JAY KUMAR YADAV ◽  
MANISH KUMAR MAURYA ◽  
KN MAURYA
Keyword(s):  
Disease Management ◽  
Disease Severity ◽  
Field Experiments ◽  
Management Strategies ◽  
Alternaria Brassicae ◽  
Effective Management ◽  
Alternaria Blight ◽  
Maximum Test ◽  
Moderately Resistant ◽  
Disease Free

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%.

scholarly journals Velocity of Spread of Wheat Stripe Rust Epidemics

2005 ◽  
Vol 95 (9) ◽  
pp. 972-982 ◽  
Author(s):  
Christina Cowger ◽  
LaRae D. Wallace ◽  
Christopher C. Mundt
Keyword(s):  
Disease Severity ◽  
Stripe Rust ◽  
Field Experiments ◽  
Average Rate ◽  
Spatial Scales ◽  
Management Strategies ◽  
Plant Diseases ◽  
Pure Stand ◽  
Wheat Stripe Rust ◽  
Competing Models

Controversy has long existed over whether plant disease epidemics spread with constant or with increasing velocity. We conducted largescale field experiments with wheat stripe rust at Madras and Hermiston, Oregon, where natural stripe rust epidemics were rare, to test these competing models. Data from three location-years were available for analysis. A susceptible winter wheat cultivar was planted in pure stand and also in a 1:4 or 1:1 mixture with a cultivar immune to the stripe rust race utilized in the experiments. Plots were 6.1 m wide and varied from 73 to 171 m in length. A 1.5 by 1.5-m focus was inoculated in either the center (2001) or upwind of the center (2002 and 2003) of each plot. Disease severity was evaluated weekly throughout the epidemics in each plot at the same points along a transect running upwind and downwind from the focus. Velocity of spread was calculated from the severity data and regressed separately on time and on distance from the focus. In all location-years and treatments, and at all levels of disease severity, velocity consistently increased linearly with distance, at an average rate of 0.59 m/week per m, and exponentially with time. Further, across epidemics there was a significant positive relationship between the apparent infection rate, r, and the rate of velocity increase in both space and time. These findings have important implications for plant diseases with a focal or partially focal character, and in particular for the effectiveness of ratereducing disease management strategies at different spatial scales.

Yield losses in canola in response to blackleg disease

2020 ◽  
Vol 100 (5) ◽  
pp. 488-494
Author(s):  
Yixiao Wang ◽  
Stephen E. Strelkov ◽  
Sheau-Fang Hwang
Keyword(s):  
Disease Severity ◽  
Field Experiments ◽  
Leptosphaeria Maculans ◽  
Economic Benefits ◽  
Control Measures ◽  
Yield Losses ◽  
Blackleg Disease ◽  
Brassica Napus L ◽  
Moderately Resistant ◽  
The Relationship

Blackleg, caused by Leptosphaeria maculans (Desm.) Ces. & De Not., is an important disease of canola (Brassica napus L.) worldwide. In Canada, blackleg is managed mainly by the cultivation of resistant or moderately resistant canola hybrids. Field experiments were conducted in Edmonton, AB, Canada, in 2017 and 2018 to determine the relationship between blackleg disease severity and yield in the moderately resistant canola hybrids ‘73-15RR’ and ‘1950RR’. Blackleg severity was rated on a 0–5 scale, where 0 = no disease and 5 = plant death. Regression analysis showed that relationships between disease severity and pod number and seed yield were best explained by second-degree quadratic equations in all site-years for both cultivars. Percentage yield loss increased by 18%–99% and 26%–86% in plants of ‘73-15RR’ and ‘1950RR’, respectively, with disease severities of 2–5 compared with plants with severities of 0–1. An improved knowledge of the relationship between blackleg severity and yield losses is important for a more accurate evaluation of the agronomic efficacy and economic benefits of control measures.

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

2021 ◽  
Author(s):  
A.S. Savitha ◽  
K. Ajithkumar ◽  
S.T. Yenjerappa
Keyword(s):  
Disease Severity ◽  
Crop Production ◽  
Management Strategies ◽  
Climatic Conditions ◽  
Morphological Variations ◽  
Alternaria Blight ◽  
Severity Of Disease ◽  
Culturally Based ◽  
Laboratory Investigations ◽  
Molecular Characters

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.

scholarly journals Evaluation of Delphinium Cultivars for Resistance to Powdery Mildew

2008 ◽  
Vol 18 (3) ◽  
pp. 407-409 ◽  
Author(s):  
Stephen N. Wegulo ◽  
Miguel Vilchez
Keyword(s):  
Powdery Mildew ◽  
Disease Severity ◽  
Field Experiments ◽  
Pearson Correlation ◽  
Rank Correlation ◽  
Correlation Coefficients ◽  
King Arthur ◽  
Moderately Resistant

Powdery mildew caused by Erysiphe aquilegiae var. ranunculi is one of the major diseases affecting field-grown delphiniums (Delphinium spp.). Two lath house and two field experiments were conducted in 2003 and 2004 to evaluate nine delphinium cultivars for resistance to the disease. ‘Blue Bird’, ‘King Arthur’, ‘Cameliard’, and ‘Galahad’ were consistently more resistant [0–1.1 disease severity (ds) on a 0–5 scale] than ‘Casa Blanca’, ‘Blue Shadow’, ‘Belladona’, and ‘Bellamosum’ (2.9–5.0 ds). ‘Oriental Blue’ was moderately resistant (0–3.3 ds). Spearman's coefficients of rank correlation were significant for all pairs of experiments (0.70 ≤ rs ≤ 0.98; P ≤ 0.0354) except for the 2003–04 field experiments (rs = 0.66; P = 0.0525). Pearson correlation coefficients between experiments (0.86 ≤ r ≤ 0.99) were highly significant (P ≤ 0.0027). Disease severity values from lath house evaluations were almost identical to those from field evaluations.

scholarly journals Screening of Blackberry and Raspberry Cultivars for Susceptibility to Fire Blight Disease in Turkey

HortScience ◽  
2014 ◽  
Vol 49 (12) ◽  
pp. 1492-1497
Author(s):  
Kubilay Kurtulus Bastas ◽  
Fikrettin Sahin
Keyword(s):  
Disease Severity ◽  
Fire Blight ◽  
Field Experiments ◽  
Bacterial Disease ◽  
Diseased Plant ◽  
Severity Rating ◽  
Phytosanitary Measures ◽  
Blight Disease ◽  
Berry Fruits ◽  
Moderately Resistant

Fire blight is the most destructive bacterial disease of rosaceous plants containing berry fruits. The present study was conducted to determine host resistance among the extensively grown raspberry cultivars (Willamette, Rubin ve Aksu Red, Heritage, and Royalty) and blackberry cultivars (Bursa-1, Bursa-2, Bursa-3, Chester, Loch Ness, and Jumbo) to Erwinia amylovora, which is the causal agent of the fire blight disease. In the greenhouse and field experiments, the plants were inoculated with two virulent strains of E. amylovora to evaluate whether cultivar–strain interactions exist. Disease index (%) and disease severity (%) were determined regarding diseased plant symptoms and classified into four susceptibility groups (HR, MR, S, and HS). Raspberry cultivar Willamette and blackberry cultivar Bursa-1 appeared to be highly susceptible with average 50% disease severity ratings. One of the raspberry cv., Royalty, was moderately resistant with an average 25% disease severity rating. This is the first study determining resistance reactions of native and common blackberry and raspberry varieties against fire blight in Turkey. As the cultivation of berries expands to new regions and larger acreages, a serious outbreak of fire blight may be potentially much more destructive in the future. Therefore, phytosanitary measures are needed to prevent any further spread of the bacterium to new blackberry- and raspberry-growing areas. The study will serve as an initial guide for growers and breeders for their appropriate raspberry and blackberry selections in Turkey.

scholarly journals Impact and Management of Diseases of Solanum tuberosum

2021 ◽  
Author(s):  
Olusola L. Oyesola ◽  
Oluwadurotimi S. Aworunse ◽  
Margaret I. Oniha ◽  
Onyemaechi H. Obiazikwor ◽  
Oluwakemi Bello ◽  
...  
Keyword(s):  
Solanum Tuberosum ◽  
Disease Management ◽  
Management Strategies ◽  
Control Measures ◽  
High Yield ◽  
World Population ◽  
High Production ◽  
Synthetic Pesticides ◽  
Plant Disease Management ◽  
Disease Free

Solanum tuberosum (Potato) is one of the essential economic crops with the potential to reduce hunger due to its high yield per unit area of land compared with many economic crops. However, its yield losses due to pest and disease attacks could be as high as 100%, depending on its tolerance level and pest and disease. Over the years, several disease management strategies have been researched, ranging from synthetic pesticides to the formulation of biopesticides as disease control measures. Moreso, recent breakthroughs in genetic engineering have simplified plant disease management strategies by developing techniques for conferring resistance on plants. Potato is a vital food crop worldwide, and with the struggle to suppress world food insecurity, effective disease management strategies must be employed for high production of quality and quantity potato, enough to feed the ever-increasing world population. Therefore, attention must be given to how disease-free potatoes can be produced to meet the unending demand for food by the continually increasing world population.

scholarly journals Fusarium basal rot: profile of an increasingly important disease in Allium spp.

2021 ◽  
Author(s):  
Dung Le ◽  
Kris Audenaert ◽  
Geert Haesaert
Keyword(s):  
Disease Management ◽  
Cultural Practices ◽  
Current Knowledge ◽  
Management Strategies ◽  
Future Directions ◽  
Basal Rot ◽  
Major Constraint ◽  
Fusarium Basal Rot ◽  
Chemical Pesticides ◽  
Important Disease

AbstractFusarium basal rot (FBR) is a soil-borne disease that affects Allium species worldwide. Although FBR has long been recognized as a major constraint to the production of economically important Allium species, information that could support disease management remains scattered. In this review, the current knowledge on the causal agents, symptomology and epidemiology, impact, and management strategies of FBR is synthesized. We highlight that FPR is associated with different complexes of several Fusarium species, of which Fusarium oxysporum and F. proliferatum are the most prevalent. These pathogenic complexes vary in composition and virulence, depending on sites and hosts, which can be challenging for disease management. Research to improve disease management using chemical pesticides, resistance cultivars, biocontrol agents, and cultural practices has achieved both promising results and limitations. Finally, research needs and future directions are proposed for the development of effective FBR management strategies.

scholarly journals Farmers’ Demand for Informal Risk Management Strategy and Weather Index Insurance: Evidence from China

2021 ◽  
Author(s):  
Yingmei Tang ◽  
Huifang Cai ◽  
Rongmao Liu
Keyword(s):  
Risk Management ◽  
Field Experiments ◽  
Management Strategies ◽  
Insurance Companies ◽  
Index Insurance ◽  
Insurance Demand ◽  
Weather Index ◽  
Weather Index Insurance ◽  
Risk Management Strategies ◽  
The Government

AbstractIn the absence of formal risk management strategies, agricultural production in China is highly vulnerable to climate change. In this study, field experiments were conducted with 344 households in Heilongjiang (Northeast China) and Jiangsu (East China) Provinces. Probit and logistic models and independent sample T-test were used to explore farmers’ demand for weather index insurance, in contrast to informal risk management strategies, and the main factors that affect demand. The results show that the farmers prefer weather index insurance to informal risk management strategies, and farmers’ characteristics have significant impacts on their adoption of risk management strategies. The variables non-agricultural labor ratio, farmers’ risk perception, education, and agricultural insurance purchase experience significantly affect farmers’ weather index insurance demand. The regression results show that the farmers’ weather index insurance demand and the influencing factors in the two provinces are different. Farmers in Heilongjiang Province have a higher participation rate than those in Jiangsu Province. The government should conduct more weather index insurance pilot programs to help farmers understand the mechanism, and insurance companies should provide more types of weather index insurance to meet farmers’ diversified needs.

EVALUATION OF ALFALFA CULTIVARS FOR REACTION TO CROWN AND ROOT ROT

1985 ◽  
Vol 65 (1) ◽  
pp. 95-98 ◽  
Author(s):  
R. MICHAUD ◽  
C. RICHARD
Keyword(s):  
Disease Severity ◽  
Root Rot ◽  
Dry Matter ◽  
Forage Yield ◽  
Dry Matter Yield ◽  
Crown And Root Rot ◽  
Disease Free

Fourteen alfalfa cultivars were grown for 2 yr at three locations and evaluated for forage dry matter yield and crown and root rot. Significant differences were found among cultivars for dry matter yield. All cultivars were affected by crown and root rot, most cultivars showing between 20 and 30% of infected tissues. Differences were observed among as well as within the cultivars for disease severity. The frequency of disease-free plants was less than 1.3% of the plants evaluated. Correlation between root rot index and forage yield was −0.87 [Formula: see text] when data were pooled over years and locations.Key words: Lucerne, root rot, cultivar, yield

scholarly journals Survival and Inoculum Production of Gibberella zeae in Wheat Residue

Plant Disease ◽  
2004 ◽  
Vol 88 (7) ◽  
pp. 724-730 ◽  
Author(s):  
S. A. Pereyra ◽  
R. Dill-Macky ◽  
A. L. Sims
Keyword(s):  
Management Strategies ◽  
Soil Surface ◽  
Triticum Aestivum L ◽  
Gibberella Zeae ◽  
Effective Management ◽  
Head Blight ◽  
Fusarium Spp ◽  
Residue Decomposition ◽  
Inoculum Production ◽  
Mesh Bags

Survival and inoculum production of Gibberella zeae (Schwein.) Petch (anamorph Fusarium graminearum (Schwabe)), the causal agent of Fusarium head blight of wheat and barley, was related to the rate of wheat (Triticum aestivum L.) residue decomposition. Infested wheat residue, comprising intact nodes, internodes, and leaf sheaths, was placed in fiberglass mesh bags on the soil surface and at 7.5- to 10-cm and 15- to 20-cm depths in chisel-plowed plots and 15 to 20 cm deep in moldboard-plowed plots in October 1997. Residue was sampled monthly from April through November during 1998 and every 2 months through April to October 1999. Buried residue decomposed faster than residue placed on the soil surface. Less than 2% of the dry-matter residue remained in buried treatments after 24 months in the field, while 25% of the residue remained in the soil-surface treatment. Survival of G. zeae on node tissues was inversely related to the residue decomposition rate. Surface residue provided a substrate for G. zeae for a longer period of time than buried residue. Twenty-four months after the initiation of the trial, the level of colonization of nodes in buried residue was half the level of colonization of residue on the soil surface. Colonization of node tissues by G. zeae decreased over time, but increased for other Fusarium spp. Ascospores of G. zeae were still produced on residue pieces after 23 months, and these spores were capable of inducing disease. Data from this research may assist in developing effective management strategies for residues infested with G. zeae.

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