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Development and Validation of a Diagrammatic Scale to Assess the Severity of Black Rot of Crucifers in Kale
Author(s) -
Nuñez Andrés Maurício Pinzón,
Monteiro Fernando Pereira,
Pacheco Leandro Pereira,
Rodríguez Gabriel Alfonso Alvarez,
Nogueira Carolina Carvalho Almeida,
Pinto Felipe Augusto Moretti Ferreira,
Medeiros Flávio Henrique Vasconcelos,
Souza Jorge Teodoro
Publication year - 2017
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/jph.12550
Subject(s) - diagrammatic reasoning , repeatability , biology , scale (ratio) , brassica , black rot , horticulture , veterinary medicine , statistics , mathematics , computer science , medicine , cartography , programming language , geography
The aim of this study was to develop a diagrammatic scale to evaluate black rot ( Xanthomonas campestris pv. compestris ) severity on kale ( Brassica oleraceae var. acephala ) leaves. The diagrammatic scale was developed and validated with eight levels of severity, ranging from 0.19 to 48.8%. More than 95% of the leaves collected from the field showed severity levels ranging from 0.1 to 21%, and 5% of the leaves showed severities higher than 22%. The validation of the scale was performed by 10 inexperienced evaluators, and the data were analysed with two methods: linear regression and Lin's statistics. Without the scale, most evaluators overestimated disease severity, whereas the use of the scale resulted in increased precision, accuracy, repeatability, and reproducibility of the estimates according to both validation methods. In conclusion, the proposed diagrammatic scale proved to be useful for assessments of black rot severity in kale leaves. The scale may be of interest to researches performing studies on epidemiology or breeding for resistance.