Development and validation of a standard area diagram set to evaluate bacterial blight on yellow passion fruit leaves

ABSTRACT Bacterial blight is one of the most important diseases of yellow passion fruit. The aim of this study was to develop and validate a set of standard area diagram (SADs) to improve the accuracy and precision of bacterial blight severity assessments on yellow passion fruit leaves. The proposed SADs, composed of illustrations of symptomatic leaves with nine severity levels (1, 2.5, 5, 10, 20, 30, 40, 50 and 62%), were evaluated by 15 raters. Accuracy, precision and reliability of the SADs were validated by quantifying and comparing the assessments performed by 15 raters with and without the use of SADs. The SADs improved accuracy (coefficient of bias, Cb = 0.940 without SADs and 0.967 with SADs), precision (correlation coefficient, r = 0.901 without SADs and 0.949 with SADs) and overall agreement (Lin’s concordance correlation coefficient, ρc = 0.863 without SADs and 0.935 with SADs) of severity estimates. Inter-rater reliability also significantly improved when the SADs were used (coefficient of determination, R2 = 0.717 without and R2 = 0.880 with the SADs; intra-class correlation, ρ = 0.798 without and ρ = 0.926 with the SADs). The developed SADs improved accuracy, precision and reliability of disease severity assessments and are recommended as an aid to assess bacterial blight on yellow passion fruit leaves.

【摘要】细菌性疫病是黄色西番莲最主要的病害之一。本研究旨在开发并验证一套标准面积图（standard area diagrams, SADs），以提升黄色西番莲叶片细菌性疫病病害严重度评估的准确性与精确性。本研究所提出的这套标准面积图包含9个严重度等级（1%、2.5%、5%、10%、20%、30%、40%、50%及62%）的病叶插画，由15名评估者开展测评。研究通过量化并对比15名评估者在使用与未使用该套标准面积图时的评估结果，验证了其准确性、精确性与可靠性。结果显示，使用该套标准面积图后，病害严重度估算的准确性（偏倚系数Cb：未使用时为0.940，使用时为0.967）、精确性（相关系数r：未使用时为0.901，使用时为0.949）以及整体一致性（林氏一致性相关系数ρc：未使用时为0.863，使用时为0.935）均得到显著提升。此外，使用标准面积图时，评估者间的信度亦明显改善（决定系数R²：未使用时为0.717，使用时为0.880；组内相关系数ρ：未使用时为0.798，使用时为0.926）。本研究开发的这套标准面积图可有效提升病害严重度评估的准确性、精确性与可靠性，推荐作为黄色西番莲叶片细菌性疫病的辅助评估工具。