Influence of temperature and leaf wetness duration in the severity of Cercospora leaf spot of beet

Marcuzzo, Leandro Luiz; Haveroth, Roberto; Nacimento, Aline

doi:10.1590/0100-5405/2111

Cited by 4 publications

(6 citation statements)

References 4 publications

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“…Favorable disease development is dependent on the amount of inoculum, warm temperatures (optimal between 22-28ºC) and high relative humidity Vathakos and Walters, 1979). Lesion development is favored by long periods (4-7 days) of high relative humidity (90 ± 5%) and/or free water after inoculation ) (Marcuzzo et al, 2016) .…”

Section: Environmental Conditionsmentioning

confidence: 99%

Resistance of garden roses to cercospora leaf spot

Kang¹,

Yan²,

Roundey³

et al. 2019

Acta Hortic.

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Cercospora rosicola is a fungal pathogen that attacks roses and causes spotting on leaves, chlorosis and in severe cases, defoliation. This disease has become more prominent in roses after the widespread use of black spot resistant roses, most likely due to the reduction of fungicide applications on roses. The objective of this thesis is to evaluate garden roses and identify QTLs for resistance to cercospora leaf spot disease. Identification of susceptible and resistant roses to cercospora leaf spot is the first step for breeding cercospora resistant rose cultivars. Cercospora leaf spot was evaluated on a percentage-based rating scale of 0-9 (0=no disease and 9=foliage covered with lesions) during spring, summer and fall of 2016 through 2018 on 130 roses in Overton and College Station, TX. Average cercospora incidence in Overton increased from 2016 to 2017, but decreased in 2018, whereas in College Station, ratings increased three-fold from 2016 (0.6) to 2018 (2.2). Most cultivars showed tolerance to the disease, particularly Rosa rugosa hybrids. However, a number of cultivars including 'American Pillar', 'John Davis', 'Carefree Delight', 'Oso Happy Candy Oh', 'Oso Easy Cherry Pie' and 'Roxanne Veranda' were highly susceptible to cercospora. In College Station, moderately high repeatability and low coefficient of variance occurred in the later months of 2017 and 2018, while in Overton, all the evaluated months in 2016 except for April showed high repeatability and low coefficient of variance. This suggests that ratings during these months are consistent, and may be the more informative months for disease evaluation. Artificial inoculation in a greenhouse setting was also attempted to identify cercospora leaf spot resistant garden roses. Although the pathogen was successfully cultured, the low sporulation, high heat and low humidity during the inoculation iii period slowed disease development. Thus, severe disease symptoms were not observed for this experiment.In 2016, fifteen diploid inter-related rose populations were evaluated for cercospora leaf spot in June, September, October and November in College Station. The estimated broad sense and narrow sense heritability were 0.83 and 0.57, respectively. A pedigree-based analysis using Visual FlexQTL software was conducted on these populations. QTLs found on LG1, LG3 andLG7 appeared in different environments. In the overall analysis, QTLs found on LG1 (0-4cM) and LG3 (36-42cM) explained 8.5% and 7.7% of the total phenotypic variance, respectively.More studies are needed to improve the strength and consistency of QTL detection in this analysis. iv DEDICATION This thesis is dedicated to my father, Yang Woo Kang and my mother, Soo Young Kim for their love and unconditional support. I am also thankful to my sisters Swanie, Serena and Sharon Kang for their patience and encouragement during times of stress. v 2006). Roses are highly heterozygous and prone to moderate inbreeding depression. The inbreeding between modern rose classes may have led to reduced fertility (Zlesa...

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Section: Environmental Conditionsmentioning

confidence: 99%

Resistance of garden roses to cercospora leaf spot

Kang¹,

Yan²,

Roundey³

et al. 2019

Acta Hortic.

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“…Os dados obtidos em diferentes tratamentos de pulverização baseado no sistema de Marcuzzo et al (2016) em relação ao sistema convencional de 5 e 7 dias quando comparados com a testemunha se ajustaram a equação linear, permitindo relacionar as variáveis testadas durante o desenvolvimento da doença (Fig. 1).…”

Section: Resultsunclassified

“…Boro com 30 dias de idade foram inoculadas com auxílio de um atomizador portátil uma suspensão (10 4 ) de conídios de C. Beticola obtidos de folhas de beterraba e caracterizado morfologicamente e após 24 horas de câmara úmida com fotoperíodo de 12 horas de luz foram transplantadas a cada um metro linear ao redor do experimento no dia da semeadura. Technology 14(2): 29-33, 2021 Para o controle da cercosporiose foram comparados os seguintes regimes de pulverização com mancozeb (80%) + oxicloreto de cobre (50%) na dose de 250 g + 200 g pc.hl -1 baseado no modelo descrito por Marcuzzo et al (2016) expresso em SE = 0,0001105 * (((x-8) 2,294387 ) * ((36-x) 0,955017 )) * (0,39219/(1+25,93072 * exp (-0,16704*y))), onde SE, representa o valor da severidade estimada (0,1 ou seja, percentual da doença /100); x, a temperatura (ºC) e y, o molhamento foliar (horas) avaliado pelas horas de umidade relativa ≥90%.…”

Section: Methodsunclassified

Análise Da Relação Entre Incidência E Severidade Foliar Da Cercosporiose Da Beterraba

Marcuzzo

Harbs

Kotkoski

et al. 2021

Glob. Sci. Technol.

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The occurrence of Cercospora leaf spot in beet can reduce the productivity and compromise the quality. The objective was to evaluate the relation between incidence and severity intensity of Cercospora leaf spot in beet. The experiment was conducted with the cultivar Boro in Catarinense Federal Institute/Campus Rio do Sul. The design was a randomized block design with four replications and six treatments made of fungicide, as the forecasting system proposed by Marcuzzo et al. with estimated severity (ES) accumulated of 0,15; 0,25, and 0,35 compared to application every 5 and 7 days in order to promote a disease gradient intensity in the years 2018 and 2019. The intensity of the disease was evaluated weekly using the severity and incidence. The data were submitted to linear regression analysis. Using the equation with the best fit in two seasons and replacing the severity value of 1% is obtained incidence of 4.8%. The estimated severity based on the incidence and the opposite enable its adequate use for technical assistance in the monitoring of Cercospora leaf spot in beet.

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“…-1 baseado no modelo descrito por MARCUZZO et al (2016b) expresso em SE = 0,0001105 * (((x-8) 2, 294387) * ((36-x) 0, 955017)) * (0,39219/(1+25,93072 * exp (-0,16704*y))), onde SE, representa o valor da severidade estimada (0,1 ou seja, percentual da doença /100); x a temperatura (ºC) e y o molhamento foliar (horas) que foi avaliado através da umidade relativa do ar ≥ 90%.…”

Section: Detalhamento Do Experimentounclassified

Progresso da cercosporiose da beterraba sob diferentes regimes de pulverização

Marcuzzo

Harbs

Kotkoski

et al. 2020

Rev. Ciênc. Agrovet.

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A cercosporiose da beterraba, causada por Cercospora beticola Sacc. é controlada por meio de pulverizações foliares com fungicidas seguindo um calendário fixo, sem considerar o progresso da doença. Um sistema de previsão pode predizer o progresso da doença e direcionar o regime de pulverizações, reduzindo o número de aplicações e otimizando o manejo da doença. Com o objetivo de avaliar o progresso da cercosporiose sob os diferentes regimes de pulverização foi aplicada a técnica de modelagem estatística conhecida por modelos mistos. Estes modelos não incluem apenas os efeitos fixos, mas também os efeitos aleatórios para cada um dos indivíduos da população em estudo. Nas safras agrícolas de 2018 e 2019, os regimes de pulverização utilizados foram baseados em sistemas com valores de severidade estimada (SE) acumulada de 0,15; 0,25, e 0,35, além dos controles padrões com intervalos de pulverizações de cinco e sete dias. A severidade acumulada da cercosporiose em função do tempo, nos cinco regimes de pulverização, foi calibrada com um modelo Gompertz ajustado pelo modelo misto e o efeito aleatório ajustado à assíntota superior. Como resultado da calibração do modelo, o tratamento com regime de pulverização com SE=0,35 não diferiu dos controles padrões com relação à área abaixo da curva de progresso da doença (AACPD), severidade final e produtividade. Os dados apresentados nesse trabalho demonstram a eficiência do sistema de previsão no manejo da cercosporiose em beterraba, com a vantagem de reduzir o número de pulverizações com fungicidas e o impacto sobre o ambiente.

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Influence of temperature and leaf wetness duration in the severity of Cercospora leaf spot of beet

Cited by 4 publications

References 4 publications

Resistance of garden roses to cercospora leaf spot

Resistance of garden roses to cercospora leaf spot

Análise Da Relação Entre Incidência E Severidade Foliar Da Cercosporiose Da Beterraba

Progresso da cercosporiose da beterraba sob diferentes regimes de pulverização

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