Development and Validation of a Diagrammatic Scale to Assess the Severity of Black Rot of Crucifers in Kale

作者：Pinzon Nunez Andres Mauricio; Monteiro Fernando Pereira^*; Pacheco Leandro Pereira; Alvarez Rodriguez Gabriel Alfonso; Almeida Nogueira Carolina Carvalho; Moretti Ferreira Pinto Felipe Augusto; Vasconcelos de Medeiros Flavio Henrique; de Souza Jorge Teodoro

来源：Journal of Phytopathology, 2017, 165(3): 195-203.

DOI：10.1111/jph.12550

• Brassica oleracea var
• acephala
• disease assessment
• disease severity
• Lin's statistics
• phytopathometry
• Xanthomonas campestris pv
• campestris

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.

• 出版日期2017-3