Virulence variability across the Alternaria spp. population determines incidence and severity of alternaria leaf spot on rapeseed

2020 ◽  
Vol 69 (3) ◽  
pp. 506-517 ◽  
Author(s):  
Hebba F. D. Al‐lami ◽  
Ming P. You ◽  
Akeel E. Mohammed ◽  
Martin J. Barbetti
Keyword(s):  
Leaf Spot ◽  
Alternaria Leaf Spot

scholarly journals Grouping sunflower genotypes for yield, oil content, and reaction to Alternaria leaf spot using GGE biplot

2015 ◽  
Vol 50 (8) ◽  
pp. 649-657 ◽  
Author(s):  
Regina Maria Villas Bôas de Campos Leite ◽  
Maria Cristina Neves de Oliveira
Keyword(s):  
Principal Component Analysis ◽  
Disease Severity ◽  
Principal Components ◽  
Leaf Spot ◽  
Oil Content ◽  
Principal Component ◽  
Component Analysis ◽  
High Yield ◽  
Gge Biplot ◽  
Alternaria Leaf Spot

Abstract:The objective of this work was to evaluate the suitability of the multivariate method of principal component analysis (PCA) using the GGE biplot software for grouping sunflower genotypes for their reaction to Alternaria leaf spot disease (Alternariaster helianthi), and for their yield and oil content. Sixty-nine genotypes were evaluated for disease severity in the field, at the R3 growth stage, in seven growing seasons, in Londrina, in the state of Paraná, Brazil, using a diagrammatic scale developed for this disease. Yield and oil content were also evaluated. Data were standardized using the software Statistica, and GGE biplot was used for PCA and graphical display of data. The first two principal components explained 77.9% of the total variation. According to the polygonal biplot using the first two principal components and three response variables, the genotypes were divided into seven sectors. Genotypes located on sectors 1 and 2 showed high yield and high oil content, respectively, and those located on sector 7 showed tolerance to the disease and high yield, despite the high disease severity. The principal component analysis using GGE biplot is an efficient method for grouping sunflower genotypes based on the studied variables.

scholarly journals Alternaria tenuissima Causing Alternaria Leaf Spot on Rubus crataegifolius in Jilin Province, China

Plant Disease ◽  
2016 ◽  
Vol 100 (11) ◽  
pp. 2321 ◽  
Author(s):  
Y. L. Cong ◽  
Z. H. Liu ◽  
B. H. Lu ◽  
L. N. Yang ◽  
X. Wang ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Jilin Province ◽  
Alternaria Tenuissima ◽  
Alternaria Leaf Spot ◽  
Rubus Crataegifolius

scholarly journals First Report of Alternaria Leaf Spot of Banana Caused by Alternaria alternata in the United States

Plant Disease ◽  
2013 ◽  
Vol 97 (8) ◽  
pp. 1116-1116 ◽  
Author(s):  
V. Parkunan ◽  
S. Li ◽  
E. G. Fonsah ◽  
P. Ji
Keyword(s):  
United States ◽  
Alternaria Alternata ◽  
Leaf Spot ◽  
Morphological Characteristics ◽  
The United States ◽  
Its Sequencing ◽  
Single Spore ◽  
First Report ◽  
Alternaria Leaf Spot ◽  
Leaf Spots

Research efforts were initiated in 2003 to identify and introduce banana (Musa spp.) cultivars suitable for production in Georgia (1). Selected cultivars have been evaluated since 2009 in Tifton Banana Garden, Tifton, GA, comprising of cold hardy, short cycle, and ornamental types. In spring and summer of 2012, 7 out of 13 cultivars (African Red, Blue Torres Island, Cacambou, Chinese Cavendish, Novaria, Raja Puri, and Veinte Cohol) showed tiny, oval (0.5 to 1.0 mm long and 0.3 to 0.9 mm wide), light to dark brown spots on the adaxial surface of the leaves. Spots were more concentrated along the midrib than the rest of the leaf and occurred on all except the newly emerged leaves. Leaf spots did not expand much in size, but the numbers approximately doubled during the season. Disease incidences on the seven cultivars ranged from 10 to 63% (10% on Blue Torres Island and 63% on Novaria), with an average of 35% when a total of 52 plants were evaluated. Six cultivars including Belle, Ice Cream, Dwarf Namwah, Kandarian, Praying Hands, and Saba did not show any spots. Tissue from infected leaves of the seven cultivars were surface sterilized with 0.5% NaOCl, plated onto potato dextrose agar (PDA) media and incubated at 25°C in the dark for 5 days. The plates were then incubated at room temperature (23 ± 2°C) under a 12-hour photoperiod for 3 days. Grayish black colonies developed from all the samples, which were further identified as Alternaria spp. based on the dark, brown, obclavate to obpyriform catenulate conidia with longitudinal and transverse septa tapering to a prominent beak attached in chains on a simple and short conidiophore (2). Conidia were 23 to 73 μm long and 15 to 35 μm wide, with a beak length of 5 to 10 μm, and had 3 to 6 transverse and 0 to 5 longitudinal septa. Single spore cultures of four isolates from four different cultivars were obtained and genomic DNA was extracted and the internal transcribed spacer (ITS1-5.8S-ITS2) regions of rDNA (562 bp) were amplified and sequenced with primers ITS1 and ITS4. MegaBLAST analysis of the four sequences showed that they were 100% identical to two Alternaria alternata isolates (GQ916545 and GQ169766). ITS sequence of a representative isolate VCT1FT1 from cv. Veinte Cohol was submitted to GenBank (JX985742). Pathogenicity assay was conducted using 1-month-old banana plants (cv. Veinte Cohol) grown in pots under greenhouse conditions (25 to 27°C). Three plants were spray inoculated with the isolate VCT1FT1 (100 ml suspension per plant containing 105 spores per ml) and incubated under 100% humidity for 2 days and then kept in the greenhouse. Three plants sprayed with water were used as a control. Leaf spots identical to those observed in the field were developed in a week on the inoculated plants but not on the non-inoculated control. The fungus was reisolated from the inoculated plants and the identity was confirmed by morphological characteristics and ITS sequencing. To our knowledge, this is the first report of Alternaria leaf spot caused by A. alternata on banana in the United States. Occurrence of the disease on some banana cultivars in Georgia provides useful information to potential producers, and the cultivars that were observed to be resistant to the disease may be more suitable for production. References: (1) E. G. Fonsah et al. J. Food Distrib. Res. 37:2, 2006. (2) E. G. Simmons. Alternaria: An identification manual. CBS Fungal Biodiversity Center, Utrecht, Netherlands, 2007.

scholarly journals First Report of an Alternaria Leaf Spot of Wheat in the U.S.A.

Plant Disease ◽  
2017 ◽  
Vol 101 (7) ◽  
pp. 1326-1326 ◽  
Author(s):  
M. R. Fulcher ◽  
J. A. Cummings ◽  
G. C. Bergstrom
Keyword(s):  
Leaf Spot ◽  
First Report ◽  
Alternaria Leaf Spot

scholarly journals Efficacy of Fungicidal Seed Treatments on Seed Borne Diseases of Green Gram

2020 ◽  
Vol 7 (3) ◽  
pp. 138-143
Author(s):  
A. J. Deshmukh ◽  
◽  
A. N. Sabalpara ◽  
R. P. Bambharolia ◽  
◽  
...  
Keyword(s):  
Leaf Spot ◽  
Seed Treatment ◽  
Leaf Blight ◽  
Green Gram ◽  
Seed Treatments ◽  
Thiophanate Methyl ◽  
Anthracnose Disease ◽  
Pooled Data ◽  
Alternaria Leaf Spot

The experiment was conducted to perceive the effect of fungicidal seed treatment on seed borne diseases of green gram on susceptible cv. GM-3 with nine different fungicides. Results revealed that dry seed treatment with either mix formulation of carbendazim + mancozeb or thiophanate methyl or carbendazim @ 2.5 g kg-1 seeds is very effective in field to control Macrophomina leaf blight, Alternaria leaf spot and Anthracnose diseases. Two years pooled data indicated that PDI of Macrophomina leaf bilght was significantly lower in dry seed treatment with carbendazim + mancozeb (0.99%, 12.90%) which was statistically at par with thiophanate methyl (1.54%, 13.80%) followed by carbendazim (0.99%, 14.06%) at 35 and 65 DAS, respectively. Two years pooled data of Alternaria leaf spot indicated that the PDI of was significantly lower in dry seed treatment with carbendazim + mancozeb (2.64%, 11.15%) which was statistically at par with thiophanate methyl (2.74%, 11.30%) followed by carbendazim (2.84%, 11.37%) at 35 and 65 DAS. Two years pooled data of Anthracnose disease indicated that the PDI of Anthracnose was significantly lower in dry seed treatment with carbendazim + mancozeb (0.81%, 6.71%).

scholarly journals Alternaria leaf spot of broccoli caused by Alternaria alternata in Bangladesh

2021 ◽  
Author(s):  
Sayma T. Nira ◽  
Md. Farhad Hossain ◽  
Nur Uddin Mahmud ◽  
Oliul Hassan ◽  
Md. Tofazzal Islam ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Leaf Spot ◽  
Maximum Growth ◽  
Pathogenicity Test ◽  
Culture Studies ◽  
Alternaria Leaf Spot ◽  
Cultural Methods ◽  
Molecular Phylogenetic ◽  
Alternaria Sp

  This study aimed to isolate and characterise the pathogen associated with Alternaria leaf spot on broccoli and to evaluate the inhibitory effects of fungicides against it. We isolated and identified the fungal pathogen as Alternaria sp. using morphological and cultural methods. Based on the aligned sequences of the internal transcribed spacer (ITS) and molecular phylogenetic analysis by the neighbour-joining method, the isolates (Ab1 and Ab2) were confirmed as Alternaria alternata. The conidia of the isolates were dark brown, cylindrical, obclavate to muriform. The conidiophores were olivaceous brown, septate, and branched. The conidial morphology of the isolates ranged from 52.4–92.4 × 10–20 μm with 2–6 transverse and 0–3 longitudinal septa. Both isolates yielded positive results in the pathogenicity test on broccoli leaves by developing brown and circular spots with concentric rings on the leaves surrounded by yellow halos. The culture studies revealed that the maximum growth of the pathogen was obtained at 30 °C and pH 6.0. Tilt 250 WC showed the highest potential in suppressing the mycelial growth of the A. alternata in vitro at a concentration as low as 50 µg/mL. The results from this study contributed to the positive identification of the pathogen and characterised A. alternata as a destructive pathogen of broccoli which may be successfully controlled by the fungicide Tilt.  

scholarly journals Biological Control of Alternaria Leaf Spot Caused by Alternaria spp. in Jerusalem Artichoke (Helianthus tuberosus L.) under Two Fertilization Regimes

Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 463 ◽  
Author(s):  
Wanalai Viriyasuthee ◽  
Sanun Jogloy ◽  
Weerasak Saksirirat ◽  
Suwita Saepaisan ◽  
Mark L. Gleason ◽  
...  
Keyword(s):  
Disease Control ◽  
Leaf Spot ◽  
Jerusalem Artichoke ◽  
Control Methods ◽  
Alternaria Leaf Spot ◽  
Resistant Varieties ◽  
Khon Kaen ◽  
Control Application ◽  
Resistant Genotypes ◽  
Reduce Disease Severity

The objectives of this study were to evaluate the efficacy of integrating resistant genotypes of Jerusalem artichoke with Trichoderma harzianum isolate T9 to control Alternaria leaf spot caused by Alternaria spp. under two fertilization regimes and to determine whether T9 application induced chitinase and β-1,3-glucanase activity in Jerusalem artichoke leaves. Six Jerusalem artichoke varieties (resistant varieties JA15, JA86, and JA116 and susceptible varieties HEL246, HEL293, and JA109) and three disease control methods (a non-inoculated control, application of T. harzianum T9, and fungicide sprays (propiconazole at a rate of 30 mL/20 L of water, 375 ppm)) was conducted in two separate trials (different fertilization regimes) at the experimental farm of the Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand. Resistant genotypes controlled Alternaria leaf spot effectively. Application of Trichoderma showed low efficacy to control Alternaria leaf spot, but in specific susceptible genotypes—HEL246 and HEL293—the application of Trichoderma could reduce disease severity up to 10%. The application of Trichoderma was associated with a rise in production of chitinase and β-1,3-glucanase in HEL246 seedlings. The number of Trichoderma propagules in soil, as well as the extent of colonization of roots and leaves, were monitored. The results indicated that application of Trichoderma had higher propagules than non-inoculated control. Neither varietal resistance nor the disease control methods used in this study impacted the yield or yield components of Jerusalem artichoke.

Relative host resistance to Alternaria leaf spot in canola and mustard varieties is defined by Alternaria species

2020 ◽  
Vol 71 (7) ◽  
pp. 689
Author(s):  
Hebba F. D. Al-Lami ◽  
Ming Pei You ◽  
Martin J. Barbetti
Keyword(s):  
Host Resistance ◽  
Leaf Spot ◽  
Disease Incidence ◽  
Severe Disease ◽  
Indian Mustard ◽  
Moderate Level ◽  
Alternaria Leaf Spot ◽  
Ethiopian Mustard ◽  
Alternaria Species ◽  
Collapse Index

Both Alternaria japonica and A. brassicae cause severe Alternaria leaf spot on canola (Brassica napus) and mustard (B. juncea). We tested 103 Brassicaceae varieties including 93 Australian canola, nine Indian mustard, and a single variety of Ethiopian mustard (B. carinata) under greenhouse conditions to identify host resistance to Alternaria leaf spot caused by A. japonica and A. brassicae in terms of disease incidence (percentage leaf disease incidence, %LDI), disease severity (percentage leaf area diseased, %LAD) and defoliation (percentage leaf collapse index, %LCI). Against A. japonica, across the three parameters, B. napus Surpass 404 CL was the most resistant (%LDI 7.5, %LAD 5.0, %LCI 0). Varieties Hyola 635 CC, Oscar, AG-Outback and Rottnest, with %LDI 15.6–19.4 and %LAD 12.5–15.6, also showed strong resistance, and with %LCI 10. Varieties 47C02, ATR-Signal and Clancy of B. napus showed a moderate level of resistance across %LDI (21.2–25.6) and %LAD (15.0–20.6), along with a low level of defoliation (%LCI 10). Varieties 46C03, 46C72, ATR-Cobbler and Granite TT of B. napus also showed a moderate level of resistance, with %LDI 23.1–28.7, %LAD 18.1–20.6 and %LCI 11.2–14.4. The significance of this resistance against A. japonica is highlighted by the severe disease on B. napus Thunder TT (%LDI 78.8, %LAD 72.5, %LCI 47.5). Against A. brassicae, all varieties showed susceptibility; however, B. napus ATR-Grace was the least susceptible in relation to disease incidence (%LDI 41.2) and severity (%LAD 36.2), and B. napus Hyola 450 TT the most susceptible (%LDI 90.0, %LAD 82.5). Variety Hurricane of B. napus was the least susceptible in terms of consequent defoliation (%LCI 11.2) and B. napus CBTM Tribune the most susceptible (%LCI 81.2). The B. carinata variety BCA 1 (ATC 95065) and all test B. juncea varieties showed susceptibility to both pathogens. These findings demonstrate high levels of resistance across Australian canola varieties against A. japonica that can be directly deployed where A. japonica is important and can be utilised by breeders for improving resistance in future varieties. By contrast, susceptibility across Australian canola and mustard varieties to A. brassicae is concerning, highlighting a need to locate suitable resistances and, until effective host resistance can be located, to develop and deploy cultural and chemical options.

Sign in / Sign up

Export Citation Format

Share Document