scholarly journals Screening of Cowpea (Vigna unguiculata ( L.)Walp) Varieties for Resistance to Leaf Spot in Southern Guinea Savannah Agro- Ecology of Nigeria

2020 ◽  
Vol 36 (2) ◽  
pp. 9-20
Author(s):  
C. Ekhuemelo ◽  
H.U. Igbor ◽  
S.J. Ocheje
Keyword(s):  
Vigna Unguiculata ◽  
Leaf Spot ◽  
Disease Incidence ◽  
Natural Infection ◽  
Growth And Yield ◽  
Leaf Spot Disease ◽  
Curvularia Lunata ◽  
Aspergillus Tamarii ◽  
Spot Disease ◽  
Cowpea Varieties

Five cowpea varieties (Vigna unguiculata (L.) Walp) namely UAM 09 1055-6, UAM 09 1051-1, IT 99k-573-1-1, IT 90k-277-2 and IT 99k-573-2-1 were investigated for fungi associated with the seed, leaf spot disease incidence and severity in Makurdi (07o 45’- 7o 50’N and 08o 45’ - 08o 50’E ; 98 m)and Otobi (7°07’ - 7°11'N and 8° 05- 8°10'E) in Benue State, Nigeria under natural infection. The effect ofleaf spot incidence and severity on the growth and yield of cowpea varieties were also evaluated. Fungi associated with the seeds and leaf spot lesions were isolated and identified. Diseased leaf samples from the study locations were found to be infected with Fusarium verticillioides, Curvularia lunata, Aspergillus tamarii Kite, Lasiodiplodia theobromae, Aspergillus flavus Link and Aspergillus niger van Tiegh, Pythium spp, Fusarium solani, Macrophomina phaseolina and Phoma sp. Otobi field had significantly higher incidence and severity of leaf spot disease than the Makurdi field. Cowpea variety IT 99k-573-1-1, IT 99k-573-2-1 and IT 90k-277-2 were classified as moderately resistant in Makurdi with a mean incidence of 22.23%, 16.97% and 16.67% respectively while varieties UAM 09 1051-1 and UAM 09 1055-6 were classified as Moderately susceptible and Highly susceptible with mean leaf spot incidence of 41.67% and 99.17% respectively. In Otobi, all the cowpea varieties screened were classified as Susceptible to leaf spot incidence with the exception of variety IT 90k-277-2 which was classified as moderately susceptible to leaf spot disease. Key words: Cowpea, leaf spot, screening, resistant, susceptible.

scholarly journals Incidence of Leaf Spot Disease Caused by Cercosporidium personatum in Resistant, Susceptible and Hybridized Population of Groundnut Cultivars

2018 ◽  
Vol 10 (10) ◽  
pp. 513
Author(s):  
M. C. Kottayi ◽  
D. D. Saoji ◽  
S. E. Pawar ◽  
A. D. Choudhary
Keyword(s):  
Leaf Spot ◽  
Disease Incidence ◽  
Resistant Mutant ◽  
Resistant Cultivar ◽  
Leaf Spot Disease ◽  
Cercosporidium Personatum ◽  
Reciprocal Crosses ◽  
Spot Disease ◽  
Mutant Lines

The disease incidence of Cercosporidium personatum in field was analysed in the hybridized population derived from the resistant mutant lines of the cultivar ICGV-87304 and TAG-24 & TG-26. Reciprocal crosses were performed using the same parents. The comparison of disease incidence in hybridized population was made with resistant cultivar Girnar-1. Susceptible parents TAG-24 and TG-26 showed disease incidence of 14.08 and 16.40%, respectively while Girnar-1 and the resistant mutant parents showed percentage infection ranging from 0.06-0.96%. The plants raised from the hybridized population showed the percent infection ranging from 0.01 to 0.02 %.

scholarly journals First report of banana (Musa acuminate L. AAA Cavendish, cv. Formosana) leaf spot disease caused by Curvularia geniculata in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Yanxiang Qi ◽  
Yanping Fu ◽  
Jun Peng ◽  
Fanyun Zeng ◽  
Yanwei Wang ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Universal Primers ◽  
Leaf Spot Disease ◽  
Leaf Margin ◽  
Conidial Suspension ◽  
Tropical Fruit ◽  
First Report ◽  
Spot Disease

Banana (Musa acuminate L.) is an important tropical fruit in China. During 2019-2020, a new leaf spot disease was observed on banana (M. acuminate L. AAA Cavendish, cv. Formosana) at two orchards of Chengmai county (19°48ʹ41.79″ N, 109°58ʹ44.95″ E), Hainan province, China. In total, the disease incidence was about 5% of banana trees (6 000 trees). The leaf spots occurred sporadically and were mostly confined to the leaf margin, and the percentage of the leaf area covered by lesions was less than 1%. Symptoms on the leaves were initially reddish brown spots that gradually expanded to ovoid-shaped lesions and eventually become necrotic, dry, and gray with a yellow halo. The conidia obtained from leaf lesions were brown, erect or curved, fusiform or elliptical, 3 to 4 septa with dimensions of 13.75 to 31.39 µm × 5.91 to 13.35 µm (avg. 22.39 × 8.83 µm). The cells of both ends were small and hyaline while the middle cells were larger and darker (Zhang et al. 2010). Morphological characteristics of the conidia matched the description of Curvularia geniculata (Tracy & Earle) Boedijn. To acquire the pathogen, tissue pieces (15 mm2) of symptomatic leaves were surface disinfected in 70% ethanol (10 s) and 0.8% NaClO (2 min), rinsed in sterile water three times, and transferred to potato dextrose agar (PDA) for three days at 28°C. Grayish green fungal colonies appeared, and then turned fluffy with grey and white aerial mycelium with age. Two representative isolates (CATAS-CG01 and CATAS-CG92) of single-spore cultures were selected for molecular identification. Genomic DNA was extracted from the two isolates, the internal transcribed spacer (ITS), large subunit ribosomal DNA (LSU rDNA), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), translation elongation factor 1-alpha (TEF1-α) and RNA polymerase II second largest subunit (RPB2) were amplified and sequenced with universal primers ITS1/ITS4, LROR/LR5, GPD1/GPD2, EF1-983F/EF1-2218R and 5F2/7cR, respectively (Huang et al. 2017; Raza et al. 2019). The sequences were deposited in GenBank (MW186196, MW186197, OK091651, OK721009 and OK491081 for CATAS-CG01; MZ734453, MZ734465, OK091652, OK721100 and OK642748 for CATAS-CG92, respectively). For phylogenetic analysis, MEGA7.0 (Kumar et al. 2016) was used to construct a Maximum Likelihood (ML) tree with 1 000 bootstrap replicates, based on a concatenation alignment of five gene sequences of the two isolates in this study as well as sequences of other Curvularia species obtained from GenBank. The cluster analysis revealed that isolates CATAS-CG01 and CATAS-CG92 were C. geniculata. Pathogenicity assays were conducted on 7-leaf-old banana seedlings. Two leaves from potted plants were stab inoculated by puncturing into 1-mm using a sterilized needle and placing 10 μl conidial suspension (2×106 conidia/ml) on the surface of wounded leaves and equal number of leaves were inoculated with sterile distilled water serving as control (three replicates). Inoculated plants were grown in the greenhouse (12 h/12 h light/dark, 28°C, 90% relative humidity). Necrotic lesions on inoculated leaves appeared seven days after inoculation, whereas control leaves remained healthy. The fungus was recovered from inoculated leaves, and its taxonomy was confirmed morphologically and molecularly, fulfilling Koch’s postulates. C. geniculata has been reported to cause leaf spot on banana in Jamaica (Meredith, 1963). To our knowledge, this is the first report of C. geniculata on banana in China.

scholarly journals First Report of a Leaf Spot on Snow Lotus Caused by Alternaria carthami in China

Plant Disease ◽  
2008 ◽  
Vol 92 (2) ◽  
pp. 318-318
Author(s):  
S. Zhao ◽  
G. Xie ◽  
H. Zhao ◽  
H. Li ◽  
C. Li
Keyword(s):  
Leaf Spot ◽  
Disease Incidence ◽  
Leaf Spot Disease ◽  
Tianshan Mountain ◽  
Causal Organism ◽  
Saussurea Involucrata ◽  
First Report ◽  
Spot Disease ◽  
Initial Symptoms ◽  
Snow Lotus

Snow lotus (Saussurea involucrata Karel. & Kir. ex Sch. Bip.) is an economically important medicinal herb increasingly grown in China in recent years. In June of 2005, a leaf spot disease on commercially grown plants was found in the QiTai Region, south of the Tianshan Mountain area of Xinjiang, China at 2,100 m above sea level. Disease incidence was approximately 60 to 70% of the plants during the 2006 and 2007 growing seasons. Initial symptoms appeared on older leaves as irregularly shaped, minute, dark brown-to-black spots, with yellow borders on the edge of the leaflet blade by July. As the disease progressed, the lesions expanded, causing the leaflets to turn brown, shrivel, and die. A fungus was consistently isolated from the margins of these lesions on potato dextrose agar. Fifty-eight isolates were obtained that produced abundant conidia in the dark. Conidia were usually solitary, rarely in chains of two, ellipsoid to obclavate, with 6 to 11 transverse and one longitudinal or oblique septum. Conidia measured 60 to 80 × 20 to 30 μm, including a filamentous beak (13 to 47 × 3.5 to 6 μm). According to the morphology, and when compared with the standard reference strains, the causal organism of leaf spot of snow lotus was identified as Alternaria carthami (1,4). Pathogenicity of the strains was tested on snow lotus seedlings at the six-leaf stage. The lower leaves of 20 plants were sprayed until runoff with conidial suspensions of 1 × 104 spores mL–1, and five plants sprayed with sterile distilled water served as controls. All plants were covered with a polyethylene bag, incubated at 25°C for 2 days, and subsequently transferred to a growth chamber at 25°C with a 16-h photoperiod. Light brown lesions developed within 10 days on leaflet margins in all inoculated plants. The pathogen was reisolated from inoculated leaves, and isolates were deposited at the Key Oasis Eco-agriculture Laboratory of Xinjiang Production and Construction Group, Xinjiang and the Institute of Biotechnology, Zhejiang University. No reports of a spot disease caused by A. carthami on snow lotus leaves have been found, although this pathogen has been reported on safflower in western Canada (3), Australia (2), India (1), and China (4). To our knowledge, this is the first report of a leaf spot caused by A. carthami on snow lotus in China. References: (1) S. Chowdhury. J. Indian Bot. Soc. 23:59, 1944. (2) J. A. G. Irwin. Aust. J. Exp. Agric. Anim. Husb. 16:921, 1976. (3) G. A. Petrie. Can. Plant Dis. Surv. 54:155, 1974. (4) T. Y. Zhang. J. Yunnan Agric. Univ.17:320, 2002.

scholarly journals First Report of a Leaf Spot Disease of Bells-of-Ireland (Moluccella laevis) Caused by Cercospora apii in California

Plant Disease ◽  
2003 ◽  
Vol 87 (2) ◽  
pp. 203-203
Author(s):  
S. T. Koike ◽  
S. A. Tjosvold ◽  
J. Z. Groenewald ◽  
P. W. Crous
Keyword(s):  
Leaf Spot ◽  
Sequence Data ◽  
Disease Incidence ◽  
Leaf Spot Disease ◽  
Conidial Suspension ◽  
Internal Transcribed Spacer Region ◽  
First Report ◽  
Spot Disease ◽  
Leaf Spots ◽  
Initial Symptoms

Bells-of-Ireland (Moluccella laevis) (Lamiaceae) is an annual plant that is field planted in coastal California (Santa Cruz County) for commercial cutflower production. In 2001, a new leaf spot disease was found in these commercially grown cutflowers. The disease was most serious in the winter-grown crops in 2001 and 2002, with a few plantings having as much as 100% disease incidence. All other plantings that were surveyed during this time had at least 50% disease. Initial symptoms consisted of gray-green leaf spots. Spots were generally oval in shape, often delimited by the major leaf veins, and later turned tan. Lesions were apparent on both adaxial and abaxial sides of the leaves. A cercosporoid fungus having fasciculate conidiophores, which formed primarily on the abaxial leaf surface, was consistently associated with the spots. Based on morphology and its host, this fungus was initially considered to be Cercospora molucellae Bremer & Petr., which was previously reported on leaves of M. laevis in Turkey (1). However, sequence data obtained from the internal transcribed spacer region (ITS1, ITS2) and the 5.8S gene (STE-U 5110, 5111; GenBank Accession Nos. AY156918 and AY156919) indicated there were no base pair differences between the bells-of-Ireland isolates from California, our own reference isolates of C. apii, as well as GenBank sequences deposited as C. apii. Based on these data, the fungus was subsequently identified as C. apii sensu lato. Pathogenicity was confirmed by spraying a conidial suspension (1.0 × 105 conidia/ml) on leaves of potted bells-of-Ireland plants, incubating the plants in a dew chamber for 24 h, and maintaining them in a greenhouse (23 to 25°C). After 2 weeks, all inoculated plants developed leaf spots that were identical to those observed in the field. C. apii was again associated with all leaf spots. Control plants, which were treated with water, did not develop any symptoms. The test was repeated and the results were similar. To our knowledge this is the first report of C. apii as a pathogen of bells-of-Ireland in California. Reference: (1) C. Chupp. A Monograph of the Fungus Genus Cercospora. Cornell University Press, Ithaca, New York, 1954.

scholarly journals First Report of Leaf Spot Disease Caused by Colletotrichum gloeosporioides on Chinese Bean Tree in China

Plant Disease ◽  
2013 ◽  
Vol 97 (1) ◽  
pp. 138-138 ◽  
Author(s):  
B. Z. Fu ◽  
M. Yang ◽  
G. Y. Li ◽  
J. R. Wu ◽  
J. Z. Zhang ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Colletotrichum Gloeosporioides ◽  
Disease Incidence ◽  
Phylogenetic Analyses ◽  
Morphological Characteristics ◽  
Leaf Spot Disease ◽  
First Report ◽  
Spot Disease ◽  
Rdna Its ◽  
Its Sequence Analysis

Chinese bean tree, Catalpa fargesii f. duciouxii (Dode) Gilmour, is an ornamental arbor plant. Its roots, leaves, and flowers have long been used for medicinal purposes in China. During July 2010, severe outbreaks of leaf spot disease on this plant occurred in Kunming, Yunnan Province. The disease incidence was greater than 90%. The symptoms on leaves began as dark brown lesions surrounded by chlorotic halos, and later became larger, round or irregular spots with gray to off-white centers surrounded by dark brown margins. Leaf tissues (3 × 3 mm), cut from the margins of lesions, were surface disinfected in 0.1% HgCl2 solution for 3 min, rinsed three times in sterile water, plated on potato dextrose agar (PDA), and incubated at 28°C. The same fungus was consistently isolated from the diseased leaves. Colonies of white-to-dark gray mycelia formed on PDA, and were slightly brown on the underside of the colony. The hyphae were achromatic, branching, septate, and 4.59 (±1.38) μm in diameter on average. Perithecia were brown to black, globose in shape, and 275.9 to 379.3 × 245.3 to 344.8 μm. Asci that formed after 3 to 4 weeks in culture were eight-spored, clavate to cylindrical. The ascospores were fusiform, slightly curved, unicellular and hyaline, and 13.05 to 24.03 × 10.68 to 16.02 μm. PCR amplification was carried out by utilizing universal rDNA-ITS primer pair ITS4/ITS5 (2). Sequencing of the PCR products of DQ1 (GenBank Accession No. JN165746) revealed 99% similarity (100% coverage) with Colletotrichum gloeosporioides isolates (GenBank Accession No. FJ456938.1, No. EU326190.1, No. DQ682572.1, and No. AY423474.1). Phylogenetic analyses (MEGA 4.1) using the neighbor-joining (NJ) algorithm placed the isolate in a well-supported cluster (>90% bootstrap value based on 1,000 replicates) with other C. gloeosporioides isolates. The pathogen was identified as C. gloeosporioides (Penz.) Penz. & Sacc. (teleomorph Glomerella cingulata (Stoneman) Spauld & H. Schrenk) based on the morphological characteristics and rDNA-ITS sequence analysis (1). To confirm pathogenicity, Koch's postulates were performed on detached leaves of C. fargesii f. duciouxii, inoculated with a solution of 1.0 × 106 conidia per ml. Symptoms similar to the original ones started to appear after 10 days, while untreated leaves remained healthy. The inoculation assay used three leaves for untreated and six leaves for treated. The experiments were repeated once. C. gloeosporioides was consistently reisolated from the diseased tissue. C. gloeosporioides is distributed worldwide causing anthracnose on a wide variety of plants (3). To the best of our knowledge, this is the first report of C. gloeosporioides causing leaf spots on C. fargesii f. duciouxii in China. References: (1) B. C. Sutton. Page 1 in: Colletotrichum: Biology, Pathology and Control. CAB International. Wallingford, UK, 1992. (2) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990. (3) J. Yan et al. Plant Dis. 95:880, 2011.

scholarly journals Evaluation of garlic, BAU-biofungicide, bion and chemical fungicides in controlling leaf spot of Taro

2017 ◽  
Vol 28 (3) ◽  
pp. 167-173
Author(s):  
MAS Sohag ◽  
MT Hossen ◽  
MS Monjil
Keyword(s):  
Field Experiment ◽  
Plant Height ◽  
Leaf Spot ◽  
Disease Incidence ◽  
Foliar Spray ◽  
Leaf Spot Disease ◽  
Spot Disease ◽  
Maximum Reduction ◽  
Before And After ◽  
Chemical Fungicides

The field experiment was conducted to evaluate the efficacy of Garlic extract @ 10%, BAU-Biofungicide @ 2%, Bion@ 0.2%, Bavistin DF (Carbendazim) @ 0.1% and Proud 250EC (Propiconazole) @ 0.1%  for controlling leaf spot disease of taro (Colocasia esculenta). Performance of these treatments was assessed by applying as cormel treatment and foliar spray. Cormel treatment under field experiment was found effective for BAU-Biofungicide and Proud 250EC. Bavistin DF and Proud 250EC was more effective than other treatments in increasing plant height and healthy leaves, and in decreasing spotted and dead leaves. Before foliar spraying, BAU-Biofungicide as cormel treatment reduced the disease incidence (46.19%) and severity (25.28%) of taro leaf spot at 180 days after sowing. As foliar spray all the treatments has significant effect on taro leaf spot. Among the treatments BAU-Biofungicide was found superior to control leaf spot of taro. BAU-Biofungicide resulted maximum reduction of disease incidence and severity and increase in number of healthy leaf followed by Bion and Proud 250EC. BAU-Biofungicide showed enhanced results in terms of disease incidence and severity of leaf spot of Taro before and after foliar spraying.Progressive Agriculture 28 (3): 167--173, 2017

First report of Epicoccum nigrum associated with leaf spot disease of cowpea (Vigna unguiculata) from India

2020 ◽  
Author(s):  
Yelandur Somaraju Deepika ◽  
Shivannegowda Mahadevakumar ◽  
Kestur Nagaraj Amruthesh ◽  
Nanjaiah Lakshmidevi
Keyword(s):  
Vigna Unguiculata ◽  
Leaf Spot ◽  
Leaf Spot Disease ◽  
First Report ◽  
Spot Disease ◽  
Epicoccum Nigrum

Effect of phosphorus on bacterial leaf spot disease incidence, and chemical composition and storage quality ofPiper betle leaves

1993 ◽  
Vol 21 (1) ◽  
pp. 75-78 ◽  
Author(s):  
A. R. Wasnikar ◽  
S. K. Khatik ◽  
M. L. Nayak ◽  
S. K. Vishwakarma ◽  
L. K. Punekar
Keyword(s):  
Chemical Composition ◽  
Leaf Spot ◽  
Disease Incidence ◽  
Leaf Spot Disease ◽  
Storage Quality ◽  
Bacterial Leaf Spot ◽  
Spot Disease ◽  
And Storage

Canola Growth Stage at Time of Infection Determines Magnitude of White Leaf Spot (Neopseudocercosporella capsellae) Impact

Plant Disease ◽  
2020 ◽  
Author(s):  
Tamsal Murtza ◽  
Ming Pei You ◽  
Martin John BARBETTI
Keyword(s):  
Plant Growth ◽  
Seed Yield ◽  
Leaf Spot ◽  
Growth Stage ◽  
Disease Incidence ◽  
Leaf Spot Disease ◽  
Leaf Stage ◽  
Spot Disease ◽  
White Leaf ◽  
Field Plots

White leaf spot (Neopseudocercosporella capsellae) is a persistent and increasingly important foliar disease for canola (Brassica napus) across southern Australia. To define the role of plant growth stage on development of the disease epidemic, we first investigated the response of different canola cultivars (Scoop and Charlton) at five Sylvester-Bradley growth stages against N. capsellae. White leaf spot disease incidence and severity was dependent upon plant growth stage and cultivar (both P < 0.001), with plants being most susceptible at plant growth stage 1,00 (cotyledon stage) followed by plant growth stage 1,04 (4th leaf stage). Then, second, to quantify the impact of this disease on canola yield, we investigated the in-field relationship of white leaf spot disease incidence and severity with seed yield loss following artificial inoculation commencing at growth stage 1.04 (4th leaf stage). White leaf spot significantly (P < 0.001) reduced seed yield by 24% in N. capsellae inoculated field plots compared with non-inoculated field plots. We believe that this is the first time that serious seed yield losses from this disease have been quantified in-field. The current study demonstrates that N. capsellae disease incidence and severity on canola is determined by host growth stage at which pathogen infestation occurs. Emerging seedling cotyledons were highly susceptible, followed by less susceptibility in first true leaves to emerge but then increasing susceptibility as plants subsequently age towards the 4th leaf stage. This explains field observances where white leaf spot readily establishes on emerging seedlings and subsequently becomes more prevalent and severe as plants age.

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