Spore Types and Spore Production of &amp;lt;i&amp;gt;Ramularia areola&amp;lt;/i&amp;gt; for Screening Cotton Germplasm for Resistance

Volponi, Jessica; Matos, Janaina N.; Girotto, Larissa; Marangoni, Mariana S.; Galbieri, Rafael; Mehta, Y. R.

doi:10.4236/ajps.2014.515254

Cited by 7 publications

(6 citation statements)

References 9 publications

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“…Differences in fluctuation of disease severity may occur due to variations in number of leaves in the different thirds of the plant, the influence of the pathogen inoculum source in the area, cultivar susceptibility levels and climatic conditions (VOLPONI et al, 2014). Thus, a precocious defoliation in the lower part of the canopy of plants is normal (PIZZATO et al, 2013;2014) in field conditions, with lesions on the leaf area of up to 67.20% (AQUINO et al, 2008a).…”

Section: Resultsmentioning

confidence: 99%

Severity of Ramularia Leaf Spot and Seed Cotton Yield in Different Sowing Times

et al. 2016

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-The ramularia leaf spot (RLS) disease causes cotton yield losses. Choosing a less susceptible cultivar and a sowing time that are less favorable to the pathogen contribute to the management of this disease. The objective of this work was to evaluate the severity of ramularia leaf spot on cotton cultivars sowed in two different times. The experiment was conducted in a triple factorial design (4x3x2), consisted of four cultivars, the three thirds of the plant and two sowing times, with four replications. Each plot was divided in two twin plots, one with fungicide application (with disease control) and the other without fungicide application (without disease control). The severity assessments were performed every seven days, considering each third of the plant with a diagrammatic scale. Yield was evaluated in each plot. There was a significant interaction between sowing times and the thirds of the plant in the plots without disease control for RLS severity, with the highest values of area under the disease progress curve (AUDPC) in the first sowing time (ST1) and in the lower third of the plant. The FMT705 cultivar had the highest and FM951LL the lowest value of AUDPC. The AUDPC of these cultivars were no statistically different in the second sowing time (ST2), but they had higher AUDPC values in the lower third. Highest yields were found with ST1 in plots with disease control, with no differences between the cultivars, however, lower yields were found in plots without disease control.Keywords: Gossypium hirsutum L. Ramularia areola. Thirds of the plant. RELAÇÃO ENTRE SEVERIDADE DA MANCHA DE RAMULÁRIA E PRODUTIVIDADE DE ALGODOEIRO EM DUAS ÉPOCAS DE SEMEADURARESUMO -A mancha de ramulária promove perdas de produtividade do algodoeiro, em que a escolha da cultivar menos suscetível e a época de semeadura menos favorável ao patógeno contribuem para o manejo da doença. O objetivo deste estudo foi avaliar a severidade da mancha de ramulária em cultivares de algodão conduzido em duas épocas de semeadura. O experimento foi conduzido em esquema fatorial triplo (4x3x2), sendo quatro cultivares, três terços da planta e duas épocas de semeadura, com quatro repetições. Cada parcela foi dividida em duas parcelas gêmeas, onde uma parcela recebeu aplicação de fungicidas (com controle) e a outra parcela não recebeu aplicação de fungicidas (sem controle). As avaliações de severidade foram feitas a cada sete dias, considerando cada terço da planta com auxílio de uma escala diagramática. A produtividade foi avaliada na área útil de cada parcela gêmea. Houve interação significativa entre as épocas de semeadura e terços da planta nas parcelas sem controle, onde os maiores valores da área abaixo da curva de progresso da severidade (AACPS) da mancha de ramulária foram observados na primeira época de semeadura (ES1) e no terço inferior da planta. As cultivares FMT 705 e FM 951 LL apresentaram menor e maior valor de AACPS, respectivamente. Na segunda época de semeadura (ES2), as cultivares não diferiram estatisticamente para AACPS,...

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Section: Resultsmentioning

confidence: 99%

Severity of Ramularia Leaf Spot and Seed Cotton Yield in Different Sowing Times

et al. 2016

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“…However, abundant sporulation on cotton leaf surface facilitates direct monoconidial isolation. Conidia can be picked up by a fine needle directly from the lesion on cotton leaves and plated in V8 juice agar culture media in Petri dishes (Volponi et al 2014). Optimal incubation occurs at 25 ± 2°C with a 12 h day length for 10 days (Galbieri et al 2015).…”

Section: Fungal Culturing and Preservationmentioning

confidence: 99%

Ramularia leaf spot: an emergent disease of cotton in Brazil

Silva

Bettiol

Suassuna

2019

Trop. plant pathol.

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Originated from the semi-arid highlands of Mexico, upland cotton (Gossypium hirsutum L.) accounts for more than 90% of world cotton fiber production. Intensively cultivated in Brazilian Cerrado since the early 1980s, the wet and warm environment of the region favors epidemics of fungal diseases such a Ramularia leaf spot, which emerged as the main disease of cotton cultivated in an area as large as one million hectares. Fungicides remain as the only resort to effectively control the disease and up to eight sequential sprays may be needed during the season. Research to improve disease management has been conducted during the last two decades including cultural, genetic, chemical and biological control methods. In this review we summarize current knowledge of the disease and the main findings and gaps on disease epidemiology and management and discuss on future direction towards a more sustainable management of a disease of greatest concern to cotton farmers in Brazil.

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“…The inoculation procedure was the same as described earlier [4] [5]. Plants inoculated with an aggressive isolate of R. areola no.…”

Section: Methodsmentioning

confidence: 99%

“…Mono-pustular isolations: Monopustular isolations of R. areola were made as reported earlier [4] [5] by picking up conidia by a fine needle from the sporulating lesions and placing them on Petri dishes containing a thin layer of water agar. Since the needle may not pick up only one conidium the isolation is referred as "monopustular".…”

Section: Methodsmentioning

confidence: 99%

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<i>Mycosphaerella areola</i>—The Teleomorph of <i>Ramularia areola</i> of Cotton in Brazil, and Its Epidemiological Significance

Mehta¹,

Galbieri²,

Marangoni³

et al. 2016

AJPS

Self Cite

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While Ramularia leaf blight of cotton caused by Ramularia areola is of top most importance for Brazil, information is lacking regarding the survival mechanism of this pathogen during the cotton-free period. The teleomorph of R. areola is expected to belong to the genus Mycosphaerella. In the present study attempts were made to verify occurrence of this teleomorph in the State of Mato Grosso, Brazil. Decaying cotton leaves were collected two months after harvest of 2014 from 44 commercial and experimental fields where aerial fungicidal applications were made or not during the crop cycle to control the Ramularia leaf blight. Examination of the decaying cotton leaves revealed presence of abundant sclerotia, spermagonia and ascoma of Mycosphaerella sp. intermingled with each other during the cotton-free period in most of the leaf samples. Mono-ascospore isolations were obtained from the ascoma and considering their cultural, morphological, pathological and DNA sequence analysis they were identified as Mycosphaerella areola. M. areola and R. areola isolates produced similar symptoms under glasshouse inoculations. Reisolation of the pathogen from the symptoms produced by M. areola isolates yielded R. areola. Some cotton leaves showing such symptoms were kept on the soil surface on plastic trays for two months under natural field condition. After this period the decaying leaves showed abundant perithecia identical to their original M. areola. ITS rDNA sequence analyses revealed identical sequences from M. areola and R. areola isolates. Occurrence and the viability of the perfect stage M. areola during the cotton-free period on the left-over stubble from one season to another were interpreted as the survival mechanism of the pathogen and were considered responsible for the Ramularia blight epidemics in the State of Mato Grosso. Disease management practices for the State of Mato Grosso are * Corresponding author.Y. R. Mehta et al. 1416 discussed. This is the first report about the occurrence of the M. areola in Brazil.

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Spore Types and Spore Production of <i>Ramularia areola</i> for Screening Cotton Germplasm for Resistance

Cited by 7 publications

References 9 publications

Severity of Ramularia Leaf Spot and Seed Cotton Yield in Different Sowing Times

Severity of Ramularia Leaf Spot and Seed Cotton Yield in Different Sowing Times

Ramularia leaf spot: an emergent disease of cotton in Brazil

<i>Mycosphaerella areola</i>—The Teleomorph of <i>Ramularia areola</i> of Cotton in Brazil, and Its Epidemiological Significance

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Spore Types and Spore Production of &lt;i&gt;Ramularia areola&lt;/i&gt; for Screening Cotton Germplasm for Resistance

Cited by 7 publications

References 9 publications

Severity of Ramularia Leaf Spot and Seed Cotton Yield in Different Sowing Times

Severity of Ramularia Leaf Spot and Seed Cotton Yield in Different Sowing Times

Ramularia leaf spot: an emergent disease of cotton in Brazil

&lt;i&gt;Mycosphaerella areola&lt;/i&gt;—The Teleomorph of &lt;i&gt;Ramularia areola&lt;/i&gt; of Cotton in Brazil, and Its Epidemiological Significance

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Spore Types and Spore Production of <i>Ramularia areola</i> for Screening Cotton Germplasm for Resistance

<i>Mycosphaerella areola</i>—The Teleomorph of <i>Ramularia areola</i> of Cotton in Brazil, and Its Epidemiological Significance