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.

Standard area diagrams to assess scab severity of entire‐margined leaves of sour passion fruit

“…Thus, R 2 improved for all raters using the SADs. Other studies have reported that the reliability of disease estimates also increases with the use of SADs (Bock et al., 2016; Debona et al., 2015; Dolinski, Duarte, Silva, & May‐De Mio, 2017; Monzani et al., 2018).…”

“…In this context, SADs are useful tools to assess the severity of plant disease because raters are able to estimate it with high accuracy and reliability. Several studies demonstrated that the use of SADs increased the accuracy, precision and reliability of the assessments of several diseases, such as blast (Rios, Debona, Duarte, & Rodrigues, 2013) and spot blotch (Domiciano, Duarte, Moreira, & Rodrigues, 2014) in wheat, Glomerella leaf spot in apple (Moreira, Duarte, & May‐De Mio, 2019), target spot in cotton (Fantin, Braga, Canteri, Dias, & Borges, 2018), frogeye leaf spot (Debona et al., 2015) and rust in soybean (Godoy, Koga, & Canteri, 2006), bacterial spot in tomato (Duan, Zhao, Wang, & Yang, 2015), rust in coffee (Capucho et al., 2011), leaf blight in eggplant (Correia et al., 2017) and bacterial blight in passion fruit (Monzani et al., 2018).…”

“…After the SADs are developed, it is mandatory to validate them before their use to improve accuracy and precision during disease severity assessments (Capucho, Zambolim, Duarte, & Vaz, 2011). In passion fruit, some SADs have been developed to assess anthracnose on fruits (Fischer et al., 2009), bacterial spot on fruits and leaves (Costa, Peixoto, Blum, de Oliveira, et al, 2019; Costa, Pires, Peixoto, Blum, & Faleiro, 2018; Monzani, da Silva, Nutter Junior, Duarte, & May‐De Mio, 2018) and scab on fruits (Costa, Peixoto, Blum, & Pires, 2019b).…”

Quantum yield, chlorophyll, and cell damage in yellow passion fruit under irrigation strategies with brackish water and potassium

“…Yellow passion fruit (Passiflora edulis Sims) is a fruit crop widely cultivated and consumed in Brazil (Monzani et al, 2018). Passion fruit has vitamin A, C, and B complex, minerals such as potassium, iron, and calcium.…”