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Subjective components of mildew assessment on spring barley

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Abstract

The severity of mildew on barley is usually assessed visually and this leads to variation between different scorers. Field assessments by four assessors were analysed to determine the nature and degree of subjective discrepancies between assessors. Two inexperienced assessors failed to detect a major effect of nitrogen due to differences in the interpretation of a scoring system. A computer-based training programme was evaluated for standardising assessments, and was found to improve assessors' accuracy. Linear regression analysis was used here to resolve the error variance into components representing the accuracy and precision of the assessors. Plots of the cumulative differences between the estimate of disease severity by each assessor and the best estimate were used to display how the discrepancies varied with the level of disease. Some modifications to the barley field scoring system are suggested to improve comparability between assessors.

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References

  • Agresti A (1990) Categorical Data Analysis. Wiley, New York

    Google Scholar 

  • Amanat P (1977) Modellversuche zur Ermittlung individueller und objektabhängiger Schätzfehler bei Pflanzenkrankheiten. Diss. Universität Giessen

  • Beresford RM and Royle DJ (1991) The assessment of infectious disease for brown rust (Puccinia hordei) of barley. Plant Pathology 40: 374–381

    Google Scholar 

  • Berger RD (1980) Measuring disease intensity. pp 28–31. In: Crop Loss Assessment. Proc EC Stakman Commem Symp Misc Pub 7, Agric Exp Stn, University of Minnesota, St Paul

  • Daamen RA (1986) Measures of disease intensity in powdery mildew (Erysiphe graminis) of winter wheat. 1. Errors in estimating pustule number. Netherlands Journal of Plant Pathology 92: 197–206

    Google Scholar 

  • Daley PF, Raschke K, Ball JT and Berry JA (1989) Topography of photosynthetic activity of leaves obtained from video images of chlorophyll fluorescence. Plant Physiology 90: 1233–1238

    Google Scholar 

  • Draper NR and Smith H (1981) Applied Regression Analysis. Second edition. Wiley, New York

    Google Scholar 

  • Filliben JJ (1975) The probability plot correlation coefficient test for normality. Technometrics 17: 111

    Google Scholar 

  • Forbes GA and Jeger MJ (1987) Factors affecting the estimation of disease intensity in simulated plant structures. Zeitschrift für Pflanzenkrankheiten und Pflanzenschutz 94: 113–120

    Google Scholar 

  • Hau B, Kranz J and König R (1989) Fehler beim Schätzen von Befallsstärken bei Pflanzenkrankheiten. Zeitschrift für Pflanzenkrankheiten und Pflanzenschutz 96: 649–674

    Google Scholar 

  • Hebert TT (1982) The rationale for the Horsfall-Barratt plant disease assessment scale. Phytopathology 72: 1269

    Google Scholar 

  • Hirst D and Naes T (1993) A graphical technique for assessing differences among a set of rankings. Journal of Chemometrics (in press)

  • Hock, J, Kranz J and Renfro BL (1992) Tests of standard diagrams for field use in assessing the tarspot disease complex of maize (Zea mays). Tropical pest management 38: 314–318

    Google Scholar 

  • Horsfall JG and Barratt RW (1945) An improved grading system for measuring plant diseases (Abstr.) Phytopathology 35: 655

    Google Scholar 

  • James WC (1971) An illustrated series of assessment keys for plant diseases, their preparation and usage. Canadian Plant Disease Survey 51: 39–65

    Google Scholar 

  • Lindow SE (1983) Estimating disease severity of single plants. Phytopathology 73: 1576–1581

    Google Scholar 

  • Naes T and Solheim R (1991) Detection and interpretation of variation within and between assessors in sensory profiling. Journal of Sensory Studies 6: 159–177

    Google Scholar 

  • Newton AC (1989) Measuring the sterol content of barley leaves infected with powdery mildew as a means of assessing partial resistance toErysiphe graminis f.sp.hordei. Plant Pathology 38: 534–540

    Google Scholar 

  • Newton AC (1990) Detection of components of partial resistance to mildew (Erysiphe graminis f.sp.hordei) incorporated into advanced breeding lines of barley using measurement of fungal cell wall sterol. Plant Pathology 39: 598–602

    Google Scholar 

  • Newton AC and Reglinski T (1993) An enzyme-linked immunosorbent assay for quantifying mildew biomass. Journal of Plant Diseases and Protection 100: 176–179

    Google Scholar 

  • Newton AC and Thomas WTB (1993) Evaluation of sources of partial resistance to mildew in barley using enzyme-linked immunosorbent assay and other assessment methods. Euphytica 66: 27–34

    Google Scholar 

  • Nilsson HE (1991) Hand-held radiometry and IR-thermography of plant diseases in field plot experiments. International Journal of Remote Sensing 12: 545–557

    Google Scholar 

  • Nutter FW (1989) Detection and measurement of plant disease gradients in peanut with a multispectral radiometer. Phytopathology 79: 958–963

    Google Scholar 

  • Nutter FW (1993) Improving the accuracy and precision of disease assessments: Selection of methods and use of computer-aided training programmes. Sixth International Congress of Plant Pathology, Montreal, Abstract S9.3, 11

  • Nutter FW, Gleason ML, Jenco JH and Christians NC (1993) Assessing the accuracy, intra-rater repeatability and inter-rater reliability of disease assessment systems. Phytopathology 83: 806–812

    Google Scholar 

  • Nutter FW, Littrell RH and Brenneman TB (1990) Utilization of a multispectral radiometer to evaluate fungicide efficacy to control late leaf spot in peanut. Phytopathology 80: 102–108

    Google Scholar 

  • Nutter FW, Teng PS and Shokes FM (1991) Disease assessment terms and concepts. Plant Disease 75: 1187–1188

    Google Scholar 

  • O'Brien RD and van Bruggen AHC (1992) Accuracy, precision and correlation to yield loss of disease severity scales for corky root of lettuce. Phytopathology 82: 91–96

    Google Scholar 

  • Parker SR and Royle DJ (1993) Sampling and monitoring disease in winter wheat. Home-Grown Cereals Authority Project Report No. 71

  • Sherwood RT, Berg CC, Hoover MR and Zeiders KE (1983) Illusions in visual assessment of Stagnospora leaf spot of orchardgrass. Phytopathology 73: 173–177

    Google Scholar 

  • Tomerlin JR and Howell TA (1988) DISTRAIN: A computer program for training people to estimate disease severity on cereal leaves. Plant Disease 72: 455–459

    Google Scholar 

  • Wetherill GB (1977) Sampling Inspection and Quality Control. Second edition. Chapman and Hall, London

    Google Scholar 

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Authors and Affiliations

  1. Mycology & Bacteriology Department, Scottish Crop Research Institute, Invergowrie, DD2 5DA, Dundee, UK

    A. C. Newton

  2. Scottish Agricultural Statistics Service, Scottish Crop Research Institute, Invergowrie, DD2 5DA, Dundee, UK

    C. A. Hackett

Authors
  1. A. C. Newton
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  2. C. A. Hackett
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Newton, A.C., Hackett, C.A. Subjective components of mildew assessment on spring barley. Eur J Plant Pathol 100, 395–412 (1994). https://doi.org/10.1007/BF01874807

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  • DOI: https://doi.org/10.1007/BF01874807

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