Resistance of standing milkvetch (Astragalus adsurgens) varieties to Embellisia astragali

2012 ◽  
Vol 63 (4) ◽  
pp. 351 ◽  
Author(s):  
B. H. Yu ◽  
Z. B. Nan ◽  
Y. Z. Li ◽  
H. L. Lin
Keyword(s):  
Disease Severity ◽  
Field Experiments ◽  
Agronomic Traits ◽  
Disease Incidence ◽  
Dry Weight ◽  
Severity Index ◽  
Field Conditions ◽  
Disease Severity Index ◽  
Greenhouse Experiments ◽  
Astragalus Adsurgens

Yellow stunt and root rot caused by Embellisia astragali are major factors contributing to declining yields of standing milkvetch (Astragalus adsurgens). The resistance of ten varieties of standing milkvetch to E. astragali was evaluated under laboratory, greenhouse, and field conditions. Seed germination/emergence, shoot and root length, plant dry weight, disease incidence, mortality, and disease severity index were monitored. The results show that Shanxi and Zhongsha No. 1 varieties had the best agronomic traits and lowest levels of disease in all experiments, while the varieties Neimeng and Ningxia had the highest susceptibility to disease. Germination/emergence differed significantly (P < 0.05) between varieties after inoculation, and compared with the control, germination/emergence of inoculated treatments of nine varieties decreased on average by 1.5% in laboratory experiments and by 4.1% in greenhouse experiments at 15 days after inoculation. Inoculation reduced shoot length by an average of 24.4% and 41.5% (P < 0.05) in laboratory and greenhouse experiments, respectively, in six of ten varieties. All varieties showed significantly (P < 0.05) lower plant dry weight following inoculation, with reductions ranging from 0.3 to 0.6 mg in the laboratory and from 82.6 to 149.4 mg in the greenhouse. Resistance to the pathogen was evaluated on the basis of disease incidence, a disease severity index (DSI), and mortality; varieties showing different resistance were grouped using cluster analysis. There were significant correlations between the results of laboratory and greenhouse experiments (r = 0.79; P < 0.01) and between greenhouse and field experiments (r = 0.83; P < 0.01) across all varieties. Multiple regression analysis between laboratory/greenhouse and field experiments on DSI suggested that screening in the laboratory/greenhouse could be an alternative method of rapidly estimating DSI under field conditions.

scholarly journals Variability of Alternaria Leaf Spot Resistance in Jerusalem Artichoke (Helianthus Tuberosus L.) Accessions Grown in a Humid Tropical Region

Agronomy ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 268 ◽  
Author(s):  
Viriyasuthee ◽  
Saksirirat ◽  
Saepaisan ◽  
Gleason ◽  
Jogloy
Keyword(s):  
Disease Severity ◽  
Leaf Spot ◽  
Disease Incidence ◽  
Jerusalem Artichoke ◽  
Severity Index ◽  
Field Conditions ◽  
Helianthus Tuberosus ◽  
Disease Severity Index ◽  
Alternaria Leaf Spot ◽  
Progress Curve

Alternaria leaf spot is an emerging disease of Jerusalem artichoke (Helianthus tuberosus L.) in tropical regions. The lack of known resistant germplasm sources is an important constraint to development of Jerusalem artichoke varieties with resistance to Alternaria leaf spot. The objectives of this study were to identify variability of Jerusalem artichoke genotypes for resistance to Alternaria leaf spot under field conditions and to investigate the relationships among resistance characters, yield, and yield components for selection of resistant varieties. Ninety six accessions of Jerusalem artichoke were evaluated in replicated trials under field conditions in early rainy and late rainy seasons in Khon Kaen, Thailand during 2014. Parameters evaluated included disease incidence, disease score, disease severity index, area under disease progress curve of disease incidence, area under disease progress curve of disease severity index, number of tubers/plants, tuber size, and fresh tuber yield. The genotypes HEL 335, HEL 256, HEL 317, HEL 308, and JA 86 were identified as sources of leaf spot resistance in both seasons. These genotypes can be used as sources of leaf spot resistance for Jerusalem artichoke breeding programs. HEL 293 and HEL 246 showed susceptibility to leaf spot disease in both seasons and should be used as standard susceptible checks.

Inheritance of resistance to Mal de Río Cuarto (MRC) disease in Zea mays (L.)

2002 ◽  
Vol 139 (1) ◽  
pp. 47-53 ◽  
Author(s):  
M. A. DI RENZO ◽  
N. C. BONAMICO ◽  
D. D. DÍAZ ◽  
J. C. SALERNO ◽  
M. M. IBAÑEZ ◽  
...  
Keyword(s):  
Zea Mays ◽  
Plant Height ◽  
Disease Severity ◽  
Agronomic Traits ◽  
Severity Index ◽  
Point Estimate ◽  
Environment Interaction ◽  
Disease Severity Index ◽  
Evaluation Activity ◽  
Genotype Environment Interaction

No genetic estimates for resistance to Mal de Río Cuarto (MRC) disease in Zea mays (L.) are currently available in the literature. Therefore, the objectives of this investigation were (i) to estimate the variance and heritability of partial resistance to MRC disease and of other agronomic traits from maize families and (ii) to examine associations among MRC disease severity values across different environments and between MRC and other agronomic traits. These estimations, obtained in an endemic area, could contribute to the design of efficient enhancement programmes and evaluation activity for the improvement of MRC resistance. The research was conducted by testing 227 F3 derived-lines from a cross between a susceptible dent line, Mo17, and a partially resistant flint line, BLS14, for MRC disease at two Río Cuarto locations in each of 2 years. The resistance of the lines, measured with a disease severity index (DSI), was normally distributed across environments. Genotypic variances were highly significant on all scoring environments. Estimates of genotype–environment interaction were also significant, suggesting that certain genotypes have little stability over different environments. For disease severity index all estimates demonstrated moderate heritabilities ranging from 0.44 to 0.56 and were similar when based on individual environments or across environment. Confidence interval widths ranged from 34.88 to 50.30% as large as the heritability point estimate. The correlations between environments were small enough to indicate that families did not rank similarly in individual environments for MRC resistance. Disease severity index correlated significantly (P<0.01) with plant height, leaf surface, leaf border, leaf length and tassel type. Heritability estimates for plant height and tassel type were 0.48 and 0.38 respectively and for the various leaf traits heritability values were very low. On the basis of the substantial genotype–environment interaction and the little association between DSI values in the different environments, selection for an increased resistance to MRC disease would require evaluation of germplasm across multiple years and locations. Tassel type would be a useful predictor of DSI and can be used effectively to improve screening procedures.

scholarly journals Wilt and Root Diseases of Asclepias tuberosa L.

Plant Disease ◽  
1997 ◽  
Vol 81 (10) ◽  
pp. 1203-1205 ◽  
Author(s):  
L. Tsror (Lahkim) ◽  
M. Hazanovski ◽  
O. Erlich ◽  
N. Dagityar
Keyword(s):  
Disease Severity ◽  
Disease Incidence ◽  
Severity Index ◽  
Disease Severity Index ◽  
Dry Rot ◽  
First Report ◽  
Binucleate Rhizoctonia ◽  
Root Diseases ◽  
Tuberous Roots

Chlorosis and wilting, followed by weak flowering or death, have been occurring in Asclepias tuberosa plants grown in Israel. Roots have been rotted and tuberous roots have shown dark lesions, sometimes with sclerotia. A binucleate Rhizoctonia sp. was detected on 39% and Pythium intermedium on 23% of diseased samples. Other organisms were less prevalent. Wilting began 7 days after seedlings were inoculated with P. intermedium or the binucleate Rhizoctonia sp. or both, with disease incidence ranging from 25 to 65% and disease severity index ranging from 0.30 to 0.85 (scale of 0 to 3). Healthy tuberous roots inoculated with the binucleate Rhizoctonia sp. exhibited dry rot within 4 to 7 days, and irregular black sclerotia of the pathogen were present 2 weeks later. This is the first report of either a binucleate Rhizoctonia sp. or P. intermedium occurring in A. tuberosa.

Alternatives for Control of Paraquat Tolerant American Black Nightshade (Solanum americana)

1991 ◽  
Vol 5 (1) ◽  
pp. 61-65 ◽  
Author(s):  
Thomas A. Bewick ◽  
William M. Stall ◽  
Stephen R. Kostewicz ◽  
Kenneth Smith
Keyword(s):  
Field Experiments ◽  
Dry Weight ◽  
Field Conditions ◽  
Metal Chelator ◽  
Greenhouse Experiments ◽  
Black Nightshade ◽  
Herbicide Treatments ◽  
American Black

Greenhouse and field experiments were conducted to identify alternative herbicide treatments for the control of a biotype of American black nightshade which has been shown to tolerate paraquat. In greenhouse experiments the combination of paraquat and the metal chelator diethyldithiocarbamate at either 1% w/v or 3% w/v, and diquat alone significantly lowered I50values, based on dry weight, when compared with paraquat alone. None of these treatments provided acceptable control (>90%) in field experiments. Treatments that controlled American black nightshade under field conditions were: monocarbamide dihydrogensulfate at 9 kg ai ha-1, monocarbamide dihydrogensulfate at 9 kg ha-1+ paraquat at 0.6 kg ha-1, lactofen at 0.6 kg ha-1, oxyfluorfen at 0.6 kg ha-1, and acifluorfen at 0.6 kg ha-1. Addition of tridiphane at 1.7 kg ha-1to paraquat at 0.6 kg ha-1did not improve control of American black nightshade under field conditions.

scholarly journals Effect of Cultural and Biological Treatments in Managing Clubroot Disease of Cabbage in Sidhuwa, Nepal

2019 ◽  
Vol 7 (1) ◽  
pp. 96-101
Author(s):  
Ashish Ghimire ◽  
Sundarman Shrestha
Keyword(s):  
Disease Control ◽  
Disease Severity ◽  
Disease Incidence ◽  
Block Design ◽  
Combined Treatment ◽  
Severity Index ◽  
Disease Severity Index ◽  
Effective Microorganisms ◽  
Clubroot Disease ◽  
Biological Treatments

The Plasmodiophora brassicae Woronin is an important soil pathogen that attacks brassicaceae family of plants. The ability of pathogen to survive in soil for many years as a resting structure even in the absence of suitable host has increased its threat by making it more devastating. Lower effectiveness of treatments applied so far and failure to completely eradicate the disease once it enters the field has posed more problems. The study was conducted at a disease infected field in Sidhuwa, Dhankuta. It was focused on the effectiveness of different cultural and biological treatments against clubroot disease under field conditions. The treatments; lime, combination of lime and vermicompost, Effective Microorganisms (EM) solution and Trichoderma viride were arranged in Randomized Complete Block Design and replicated four times. The yield and yield attributing parameters and clubroot scale were recorded at the time of harvest. Values like Disease Incidence, Disease Severity Index and Disease Control Percentage were calculated based on clubroot scale value. The treatments showed no significant influence on vegetative parameters of the plants and on disease incidence. However, the combined treatment of lime and vermicompost was found to be most effective regarding disease severity and disease control i.e. the least Disease Severity Index (31.25%) and highest Disease Control Percentage (50.94%) compared to the control were obtained from the combined treatment of lime and vermicompost. Effective Microorganisms showed the highest disease severity. The combination of lime and vermicompost used as a treatment yielded highest marketable head weight (1.779 kg) and head diameter (19.90 cm). Int. J. Appl. Sci. Biotechnol. Vol 7(1): 96-101

scholarly journals Effect of weather parameters, host resistance and sowing date on disease severity and temporal dynamics of Fusarium wilt in chickpea (Cicer arietinum L.)

2022 ◽  
Vol 24 (1) ◽  
Author(s):  
ANNIE KHANNA ◽  
KUSHAL RAJ ◽  
PANKAJ KUMAR
Keyword(s):  
Disease Severity ◽  
Cicer Arietinum ◽  
Fusarium Wilt ◽  
Field Experiments ◽  
Severity Index ◽  
Susceptible Variety ◽  
Resistant Variety ◽  
Disease Severity Index ◽  
Cicer Arietinum L ◽  
Weather Parameters

Fusarium wilt incited by Fusarium oxysporum f. sp. ciceris is an economically damaging disease of chickpea (Cicer arietinum L.). Field experiments on epidemiological studies revealed that sowing during second fortnight of November curtailed the disease severity index (22.50 and 20.83% during 2018-19 and 2019-20, respectively) whereas, sowing during first fortnight of October enhanced the disease severity index (34.86 and 30.41%). The area under disease progress curve was significantly higher in susceptible variety JG 62 and was the least in resistant variety HC 1. The correlation analysis exhibited positive correlation of disease severity index with maximum and minimum temperature while negative correlation with relative humidity morning and evening, irrespective of date of sowing. The principal component analysis depicted resistance index, sowing time and weather parameters as positional factors in determining Fusarium wilt progression.  In susceptible variety, Gompertz model was the best fitted model for simulating the Fusarium wilt epidemic over time.

EVALUATION OF NONIONIC SURFACTANTS FOR CONTROL OF CLUBROOT OF CABBAGE USING BAREROOT AND PLUG TRANSPLANTS OF TWO CULTIVARS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 607b-607
Author(s):  
W. Tietjen ◽  
P.J. Nitzsche ◽  
W.P. Cowgill ◽  
M.H. Maletta ◽  
S.A. Johnston
Keyword(s):  
Brassica Oleracea ◽  
Disease Severity ◽  
Nonionic Surfactants ◽  
Plasmodiophora Brassicae ◽  
Severity Index ◽  
Effective Control ◽  
Disease Severity Index

`Market Prize' and `Bravo' cabbage (Brassica oleracea Var. capitata L.), transplanted as peat plug and bareroot plants into a field naturally infested with Plasmodiophora brassicae, Woronin, were treated immediately after planting with a liquid or a granular surfactant. APSA 80™, applied in transplant water, significantly reduced percent clubbing and disease severity index (DSI) compared to control treatments. Miller Soil Surfactant Granular™ did not significantly reduce percent clubbing or DSI. There was a significant effect of cultivar on percent clubbing and DSI. There was no significant effect of transplant type on percent clubbing or DSI. This year's study culminates five years of investigation of surfactants for clubroot control. Specific surfactants have proven to be an effective control of clubroot in cabbage. Chemical names used: nonylphenoxypolyethoxyethanol (APSA 80™); alpha-alkanoic-hydro omega-hydroxy poly (oxyethylene) (Miller Soil Surfactant Granular™).

scholarly journals Summer Heat and Low Soil Organic Matter Influence Severity of Hazelnut Cytospora Canker

2014 ◽  
Vol 104 (4) ◽  
pp. 387-395 ◽  
Author(s):  
Jay Ram Lamichhane ◽  
Alfredo Fabi ◽  
Leonardo Varvaro
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Disease Severity ◽  
Severity Index ◽  
Stress Factors ◽  
Disease Severity Index ◽  
Positive Correlation ◽  
Summer Heat ◽  
Production Areas ◽  
Cytospora Canker

Cytospora canker, caused by the fungus Cytospora corylicola, is present in hazelnut production areas worldwide. The disease is widespread throughout the main production areas of Italy. The causal agent is considered to be a secondary invader of damaged tissue that attacks mainly stressed plants. However, little is known of disease severity and stress factors that predispose plants to infection. In particular, the role of pedoclimatic factors was investigated. Direct survey indicated that disease severity varied across several study sites. Geostatistics showed a strong positive correlation between disease severity index and summer heat (r = 0.80 and 0.91 for July and August, respectively) and strong negative correlation between disease severity index and soil organic matter (r = –0.78). A moderate positive correlation between disease severity index and magnesium/potassium ratio (r = 0.58) and moderate negative correlations between disease severity index and total soil nitrogen (r = –0.53), thermal shock (r = –0.46), and rainfall (r = –0.53) were determined. No significant correlation between disease severity index and soil aluminum (r = –0.35), soil pH (r = –0.01), and plant age (r = –0.38) was found.

scholarly journals The relationship between SPAD chlorophyll and disease severity index in Ganoderma-infected oil palm seedlings

2019 ◽  
Vol 17 (3) ◽  
pp. 355-358 ◽  
Author(s):  
M.R.M. Rakib ◽  
A.H. Borhan ◽  
A.N. Jawahir
Keyword(s):  
Chlorophyll Content ◽  
Disease Severity ◽  
Oil Palm ◽  
Single Photon ◽  
Linear Trend ◽  
Severity Index ◽  
Quadratic Model ◽  
Wood Block ◽  
Disease Severity Index ◽  
The Relationship

Establishment of disease in oil palm seedlings through artificial inoculation of Ganoderma are widely used for studies of various aspects of plant pathology, including epidemiology, etiology, disease resistance, host-parasite interaction and disease control. The estimation of chlorophyll content in the infected seedlings possibly could provide a good indicator for degree of disease or infection, and changes during pathogenesis. Thus, the objective of this study was to evaluate the relationship between disease severity index (DSI) and chlorophyll content in Ganoderma infected oil palm seedlings. Three-month-old oil palm seedlings were infected with Ganoderma inoculum on rubber wood block (RWB), where 44 isolates of Ganoderma were tested. Disease severity index (DSI) and chlorophyll content using a single-photon avalanche diode (SPAD) meter were recorded at 4 weeks interval for a period of 24 weeks after inoculation (WAI). Pearson's correlation analysis and regression analysis were performed to evaluate the relationship between the variables. It was found that the relationship between DSI and SPAD chlorophyll value was inversely proportional (R = -0.92) in a linear trend (R2 = 0.85). Furthermore, the increasing trend of the DSI across the weeks were fitted in a quadratic model (R2 = 0.99). In contrast, the SPAD chlorophyll value declined in a linear trend (R2 = 0.98). The SPAD chlorophyll value could be considered as a better alternative over the DSI as the SPAD chlorophyll value was strongly related to DSI, as well as able to detect physiological changes in the infected oil palm seedlings at the early stages of pathogenesis. J Bangladesh Agril Univ 17(3): 355–358, 2019

scholarly journals MANAGEMENT OF APHID BORNE POTATO VIRUS Y (PVY) THROUGH CHEMICAL AND BIO-CHEMICAL METHODS

2017 ◽  
Vol 2 (2) ◽  
pp. 159
Author(s):  
Altaf Hussain ◽  
Muhammad Arif ◽  
Aqleem Abbas
Keyword(s):  
Disease Severity ◽  
Potato Virus Y ◽  
Disease Incidence ◽  
Field Conditions ◽  
Individual State ◽  
Chemical Methods ◽  
Neem Extract ◽  
Severity Level ◽  
Level 1 ◽  
Disease Severity Level

The aim of this study was the management of potato virus Y (PVY) in potato cv. Desiree through chemical and non-chemical methods. The experiment was carried out at the New Developmental Farm (NDF), The University of Agriculture, Peshawar during spring season, 2014 under field conditions. One of the major objectives of the experiment was to assess the effectiveness of the treatments application in their individual state as well as in combinations under field conditions. The treatments were mineral oil, insecticide, biocide and their combinations. Among various treatments, Diver was effective with disease severity level (1) and % disease incidence (40) in individual state and in combination (Diver + Confidor) and (Diver + Confidor + Neem extract) gave good results with % disease incidence (33.33) and with disease severity level (1). Neem extract was found to be less effective when used individually with % disease incidence (56.66) and with disease severity level (3), whereas Confidor when applied individually was more effective than Neem extract with % disease incidence (50) and with disease severity level (2). Moreover Diver in combination with Neem extract was found to be less effective in management of PVY as compared to Diver in combination with Confidor with % disease incidence (40) and disease severity level (1). Three aphid species were found in the field i.e Myzus persicae (Sulzer), Aphid gossypii (Glover) and Macrosiphum euphorbiae (Thomas). In case of aphid’s population, Confidor was more effective in reducing aphid’s population as compared to Diver and Neem extract. Finally, it can be concluded that Diver alone was more effective in the management of PVY. However in combination, Diver with Confidor significantly managed PVY under field conditions

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