A new diagrammatic scale for the assessment of northern corn leaf blight

Vieira, Rafael Augusto; Mesquini, Renata Moreschi; Silva, Cleiltan N.; Hata, Fernando Teruhiko; Tessmann, Dauri José; Scapim, Carlos Alberto

doi:10.1016/j.cropro.2011.04.018

Cited by 42 publications

(26 citation statements)

References 5 publications

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“…Accuracy increased when the scale was used to evaluate black rot in coconut fruits (Figure 2), which is similar to results reported for other diseases (4, 23,24).…”

Section: Resultssupporting

confidence: 75%

Diagrammatic scale of severity for postharvest black rot (Ceratocystis paradoxa) in coconut palm fruits

Santos

Mussi‐Dias

Freire³

et al. 2017

Summa phytopathol.

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One of the major bottlenecks in the postharvest commercialization of coconut fruits is the black rot disease, caused by the fungus Ceratocystis paradoxa. This disease has been neglected in the main production areas or associated with other coconut diseases. To date, there are no standardized methods for assessing the intensity of such a problem. In this sense, the aim of our study was to prepare and validate a diagrammatic scale to evaluate the disease severity in coconut fruits. We also tested the scale applicability comparing distinct C. paradoxa isolates on inoculated fruits. ABSTRACT quantification, the fruit longitudinal sectioning was necessary, allowing the visualization of internal symptoms. The proposed scale showed good repeatability and high reproducibility, with absolute errors around 8%, while the coefficient of determination presented an average of 91% with the aid of the scale and of 59% without the scale. In addition, symptom analyses showed that the outer necrosis does not match the internal damage. Therefore, we suggest in this study that the severity estimate of this disease be obtained by using the presented scale. RESUMOUm dos principais problemas na comercialização de frutos de coco em pós-colheita tem sido a podridão negra, causada pelo fungo Ceratocystis paradoxa. Esta doença tem sido negligenciada nas principais áreas produtoras ou associadas à outras doenças da cultura. Até o presente momento, não existem métodos padronizados para a avaliação da intensidade de tal problema. Neste sentido, o objetivo do nosso estudo foi preparar e validar uma escala diagramática para avaliar a severidade da doença em frutos de coco. Com isso, foi possível testar a aplicabilidade da escala comparando diferentes isolados de C. paradoxa em Santos, P.H.D.; Mussi-Dias, V.; Freire, M.G.M.; Carvalho, B.M.; Silveira, S.F. Escala Diagramática para avaliação da severidade da podridão negra (Ceratocystis paradoxa) na pós colheita em coco. Summa Phytopathologica, v.43, n.4, p.269-275, 2017. frutos inoculados. Para esta quantificação, o seccionamento longitudinal do fruto foi necessário, permitindo a visualização interna dos sintomas. Dessa forma, a escala proposta apresentou boa repetibilidade e alta reprodutibilidade, com erros absolutos em torno de 8% e coeficientes de determinação com médias de 91% com o auxílio da escala e de 59% sem a escala. Além disso, as análises sintomáticas mostraram que uma necrose exterior não corresponde ao dano interno. Por isso, indica-se neste trabalho, a estimativa da severidade desta doença através da escala apresentada.

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“…Accuracy increased when the scale was used to evaluate black rot in coconut fruits (Figure 2), which is similar to results reported for other diseases (4, 23,24).…”

Section: Resultssupporting

confidence: 75%

Diagrammatic scale of severity for postharvest black rot (Ceratocystis paradoxa) in coconut palm fruits

Santos

Mussi‐Dias

Freire³

et al. 2017

Summa phytopathol.

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“…Disease severity over estimation can be corrected by the initial training of raters (Nutter and Schultz, 1995). Therefore, the use of diagrammatic scale increased the precision of visual estimates, similar to what is seen in other studies of diagrammatic scale validation (Capucho et al, 2010;Vieira et al, 2014;Freitaset al, 2015).…”

supporting

confidence: 52%

Evaluation of Postharvest Stem-End Rot on Coconut Fruits

Mussi‐Dias¹,

Freire²

2016

JAES

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The stem-end rot on coconut fruits is the main postharvest crop disease, causing heavy losses especially when the product is sold fresh. The efficient and practical control of this plant disease has been difficult to date, such as the damage evaluation, which has been done exclusively by the incidence of the disease. However, the incidence parameter alone does not provide a satisfactory understanding of the lesion area and the intensity it can achieve during the storage period, and about the environmental conditions in which the fruits are subjected to the aggressiveness of Lasiodiplodiatheobromae, when it is confirmed as the causal agent of the disease, and the control measures applied. Thus, in this study we propose to evaluate the basal rot development in coconut fruits during postharvest and to prepare and validate a diagrammatic scale to enable the estimation of disease severity. Fruits were inoculated and the external and internal symptoms of disease developments were photographed to measure the damaged area, which were grouped into eight disease levels. Sixty images were assessed by 30 evaluators for three consecutive times at intervals of 7 days and data were subjected to linear regression analysis. Hence, it was possible to create and validate a diagrammatic scale to evaluate the disease severity on coconut fruits with an accurate, precise and reproducible manner. Furthermore, the proposed scale allowed us to distinguish the aggressiveness of different isolates of the fungus through the symptoms of internal fruit rot.

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“…Severity of NLB was evaluated on the third fully expanded leaf, from base to top, of inoculated plants using a set of standard area diagrams (Vieira et al 2014) at 5, 10, 15, and 20 days after inoculation (dai).…”

Section: Methodsmentioning

confidence: 99%

Changes in leaf gas exchange, chlorophyll a fluorescence, and antioxidantsin maize leaves infected by Exserohilum turcicum

Silveira¹,

Milagres²,

Corrêa³

et al. 2019

Biol. plant.

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Considering the importance of northern leaf blight, caused by Exserohilum turcicum, to decrease maize yield, this study evaluated electrolyte leakage, content of H2O2, malondialdehyde (MDA), chlorophyll (Chl) a, Chl b, and carotenoids (CAR), and activities of superoxide dismutase, catalase, ascorbate peroxidase, peroxidase, glutathione reductase, glutathione-S-transferase, and glutathione peroxidase, as well as expressions of superoxide dismutase (sod), catalase (cat 1), ascorbate peroxidase (apx 2), peroxidase (pox), glutathione reductase (gr 1), and glutathione-S-transferase (gst 23) genes, and leaf gas exchange and Chl a fluorescence parameters in maize leaves infected with E. turcicum. The content of H2O2 and MDA was high at 15 and 20 d after inoculation (dai) and electrolyte leakage was high from 10 dai onward in infected leaves. Net assimilation rate, stomatal conductance to water vapour, transpiration rate, internal CO2 concentration, maximum quantum yield of photosystem (PS) II, and effective quantum yield of PS II significantly decreased as the disease developed. Quantum yield of regulated energy dissipation significantly increased at 10 and 15 dai but decreased at 20 dai whereas the quantum yield of non-regulated energy dissipation significantly increased at 15 and 20 dai. The content of Chl a, Chl b, and CAR decreased in infected leaves. The activities of the enzymes increased, and the relative expressions of the genes sod, cat 1, apx 2, pox, gr 1, and gst 23 were higher in infected leaves compared to non-infected ones mainly from 10 dai onward. In conclusion, photosynthesis in infected leaves was dramatically affected and a late involvement of the antioxidant metabolism was not sufficiently helpful to counteract the deleterious effects of fungal infection.

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A new diagrammatic scale for the assessment of northern corn leaf blight

Cited by 42 publications

References 5 publications

Diagrammatic scale of severity for postharvest black rot (Ceratocystis paradoxa) in coconut palm fruits

Diagrammatic scale of severity for postharvest black rot (Ceratocystis paradoxa) in coconut palm fruits

Evaluation of Postharvest Stem-End Rot on Coconut Fruits

Changes in leaf gas exchange, chlorophyll a fluorescence, and antioxidantsin maize leaves infected by Exserohilum turcicum

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