Abstract
This study aimed to develop, evaluate and compare standard area diagram sets (SADs) based on whole compound leaves or single central leaflets of cassava as aids to estimate the severity of brown leaf spot (BLS), caused by Passalora henningsii. The proposed SADs illustrated either compound leaves or central leaflets with eight disease severities ranging from 0.1 to 24%. The SADs were validated by eight raters with no previous experience in disease assessment. There was a positive association between actual severity on compound leaves and central leaflets (r = 0.89; p < 0.01). Lin’s concordance correlation analysis of estimated versus actual disease severity (based on image analysis) showed that all statistics (υ, u, Cb, r and ρc) were improved by using both SADs. Similarly, by analysing the coefficient of determination and intra-class correlation coefficient, the estimates of severity were more reliable using these SADs. Further field tests demonstrated both SADs were suitable for assessment of BLS in different growing areas and as an aid to estimate severity in a germplasm collection of cassava. However, using the SADs based on central leaflets resulted in more rapid estimates compared to using that based on compound leaves (a reduction of 25 and 31% of time taken for the assessments in different growing areas and in the germplasm collection, respectively) with no loss of accuracy. This is the first time that assessment efficiency of diseased whole organ and organ subunits has been performed. Based on the results, the SADs using central leaflets is preferred in situations that require a large number of assessments in a short time frame.
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Bock, C. H., Parker, P. E., Cook, A. Z., Riley, T., & Gottwald, T. R. (2009). Comparison of assessment of citrus canker foliar symptoms by experienced and inexperienced raters. Plant Disease, 93, 412–424.
Bock, C. H., Poole, G. H., Parker, P. E., & Gottwald, T. R. (2010). Plant disease severity estimated visually, by digital photography and image analysis, and by hyperspectral imaging. Critical Reviews in Plant Sciences, 29, 59–107.
Bock, C. H., Wood, B. W., & Gottwald, T. R. (2013). Pecan scab severity – effects of assessment methods. Plant Disease, 97, 675–684.
Bock, C. H., Chiang, K. S., & Del Ponte, E. M. (2016a). Accuracy of plant specimen disease severity estimates: concepts, history, methods, ramifications and challenges for the future. CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources, 11, 039: 1–13.
Bock, C. H., Hotchkiss, M. W., & Wood, B. W. (2016b). Assessing disease severity: accuracy and reliability of rater estimates in relation to number of diagrams in a standard area diagram set. Plant Pathology, 65, 261–272.
Capucho, A., Zambolim, L., Duarte, H. S. S., Parreira, D. F., Ferreira, P. A., Lanza, F. E., Costa, R. V., Casela, C. R., & Cota, L. V. (2010). Influence of leaf position that correspond to whole plant severity and diagrammatic scale for white spot of corn. Crop Protection, 29, 1015–1020.
Chiang, K. S., Bock, C. H., Lee, I. H., El Jarroudi, M., & Delfosse, P. (2016). Plant disease severity assessment – how rater bias, assessment method, and experimental design affect hypothesis testing and resource use efficiency. Phytopathology, 106, 1451–1464.
Cochran, W. G. (1977). Sampling techniques. New York: John Wiley & Sons.
Correia, K. C., Queiroz, J. V. J., Martins, R. B., Nicoli, A., Del Ponte, E. M., & Michereff, S. J. (2017). Development and evaluation of a standard area diagram set for the severity of phomopsis leaf blight on eggplant. European Journal of Plant Pathology, 149, 269–276.
Del Ponte, E. M., Pethybridge, S. J., Bock, C. H., Michereff, S. J., Machado, F. J., & Spolti, P. (2017). Standard area diagrams for aiding severity estimation: scientometrics, pathosystems and methodological trends in the last 25 years. Phytopathology, 107, 1161–1174.
Dolinski, M. A., Duarte, H. S. S., Silva, J. B., & May De Mio, L. L. (2017). Development and validation of a standard area diagram set for assessment of peach rust. European Journal of Plant Pathology, 148, 817–824.
Duarte, H. S. S., Zambolim, L., Capucho, A. S., Nogueira Júnior, A. F., Rosado, A. W. C., Cardoso, C. R., Paul, P. A., & Mizubuti, E. S. G. (2013). Development and validation of a set of standard area diagrams to estimate severity of potato early blight. European Journal of Plant Pathology, 137, 249–257.
FAO. (2017). FAOSTAT. [http://faostat3.fao.org/home/index.html]. Accessed on 18 October 2017.
Freitas, J. P. X., Diniz, R. P., Oliveira, S. A. S., Santos, V. S., & Oliveira, E. J. (2017). Inbreeding depression for severity caused by leaf diseases in cassava. Euphytica, 213, 205. https://doi.org/10.1007/s10681-017-1995-0.
Godoy, C. V., Koga, L. J., & Canteri, M. G. (2006). Diagrammatic scale for assessment of soybean rust severity. Fitopatologia Brasileira, 31, 63–68.
González-Domínguez, E., Martins, R. B., Del Ponte, E. M., Michereff, S. J., García-Jiménez, J., & Armengol, J. (2014). Development and validation of a standard area diagram set to aid assessment of severity of loquat scab on fruit. European Journal of Plant Pathology, 139, 419–428.
Hillocks, R. J., & Wydra, K. (2002). Bacterial, fungal and nematode diseases. In R. J. Hillocks, J. M. Thresh, & A. Bellotti (Eds.), Cassava: Biology, production, and utilization (pp. 261–280). Wallingford: CABI.
Klosowski, A. C., Ruaro, L., Bespalhok Filho, J. C., & May De Mio, L. L. (2013). Proposal and validation of diagrammatic scale for assessment of orange rust of sugarcane. Tropical Plant Pathology, 38, 166–171.
Lamari, L. (2008). ASSESS 2.0: image analysis software for plant disease quantification. St. Paul: APS Press.
Lebot, V. (2009). Tropical root and tuber crops: Cassava, sweet potato, yams. Wallingford: CABI.
Lin, L. I. (1989). A concordance correlation coefficient to evaluate reproducibility. Biometrics, 45, 255–268.
Madden, L. V., Hughes, G., & Van den Bosch, F. (2007). The study of plant disease epidemics. St. Paul: APS Press.
Massola, N. S., Bedendo, I. P., & Oliveira, S. A. S. (2016). Doenças da Mandioca. In H. Himati, L. Amorim, J. A. M. Rezende, A. Bergamin Filho, & L. E. A. Camargo (Eds.), Manual de Fitopatologia: Doenças de Plantas Cultivadas (pp. 515–522). Ouro Fino: Agronômica Ceres.
Michereff, S. J., Pedrosa, R. A., Noronha, M. A., Martins, R. B., & Silva, F. V. (1998). Escala diagramática e tamanho de amostras para avaliação da severidade da mancha parda da mandioca (Cercosporidium henningsii). Agrotrópica, 10, 143–148.
Nita, M., Ellis, M. D., & Madden, L. V. (2003). Reliability and accuracy of visual estimation of Phomopsis leaf blight of strawberry. Phytopathology, 93, 995–1005.
Nutter Jr., F. W., & Schultz, P. M. (1995). Improving the accuracy and precision of disease assessments: selection of methods and use of computer-aided training programs. Canadian Journal of Plant Pathology, 17, 174–184.
Parker, S. R., Shaw, M. W., & Royle, D. J. (1995). Reliable measurement of disease severity. Aspects of Applied Biology, 43, 205–214.
Reddy, P. P. (2015). Plant protection in tropical root and tuber crops. New Delhi: Springer India.
Rios, J. A., Debona, D., Duarte, H. S. S., & Rodrigues, F. A. (2013). Development and validation of a standard area diagram set to assess blast severity on wheat leaves. European Journal of Plant Pathology, 136, 603–611.
Santos, R. P., Carmo, M. G. F., Parraga, M. S., Macagnan, D., & Lopes, C. A. (2004). Avaliação de cultivares de mandioca, para consumo in natura, quanto à resistência à mancha parda da folha. Horticultura Brasileira, 22, 232–237.
Schwanck, A. A., & Del Ponte, E. M. (2014). Accuracy and reliability of severity estimates using linear or logarithmic disease diagram sets in true colour or black and white: a study case for rice brown spot. Journal of Phytopathology, 162, 670–682.
Shoukri, M. M., & Pause, C. A. (1999). Statistical methods for health sciences. Boca Raton: CRC Press.
Takatsu, A., Fukuda, S., Hahn, S. K., & Caveness, F. E. (1990). Integrated pest management for tropical root and tuber crops. In S. K. Hahn & F. E. Caveness (Eds.), Proceedings of the workshop on the global status and of prospects for IPM of root and tuber crops (pp. 121–131). Ibadan: IITA.
Teri, J. M., Thurston, H. D., & Lozano, J. C. (1980). Effect of brown leaf spot and cercospora leaf blight on cassava productivity. Tropical Agriculture, 3, 239–243.
Teri, J. M., Lozano, J. C., & Thurston, D. D. (1981). Epidemiology of cassava brown leaf spot. Fitopatologia Brasileira, 6, 341–344.
Yadav, N. V. S., de Vos, S. M., Bock, C. H., & Wood, B. W. (2013). Development and validation of standard area diagrams to aid assessment of pecan scab symptoms on fruit. Plant Pathology, 62, 325–335.
Acknowledgements
The authors thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Fundação de Amparo à Ciência e Tecnologia de Pernambuco (FACEPE) for their financial support (CNPq 454010/2014-1 and FACEPE APQ-1542-5.01/15) and the scholarship for F.A.S. Lima Filho (FACEPE IBPG-0175-5.01/14). S.J. Michereff also acknowledges the CNPq research fellowship.
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Lima Filho, F.A.S., Leite, Í.C.H.L., Capucho, A.S. et al. Accuracy and efficiency of assessments of cassava brown leaf spot aided by standard area diagram sets based on whole compound leaves or single central leaflets. Eur J Plant Pathol 153, 627–638 (2019). https://doi.org/10.1007/s10658-018-1586-5
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DOI: https://doi.org/10.1007/s10658-018-1586-5