دورية
Methods for Sampling and Assessment in Relation to the Spatial Pattern of Phoma Stem Canker (Leptosphaeria maculans) in Oilseed Rape
| العنوان: | Methods for Sampling and Assessment in Relation to the Spatial Pattern of Phoma Stem Canker (Leptosphaeria maculans) in Oilseed Rape |
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| المؤلفون: | Aubertot, J.-N., Schott, J.-J., Penaud, A., Brun, H., Doré, T. |
| المصدر: | European Journal of Plant Pathology; February 2004, Vol. 110 Issue: 2 p183-192, 10p |
| مستخلص: | A sound assessment of phoma stem canker symptoms is needed to develop epidemiological, agronomical and physiological studies on the pathosystem. A specific analysis was therefore carried out to: (i) compare four methods of crown canker assessment; (ii) test the among and within assessor repeatability of one of the methods compared; (iii) characterise the spatial pattern of the disease; and (iv) define the sample size required to achieve a given level of disease assessment precision. The methods compared examined the symptoms with different procedures and graded the plants observed into six severity classes. A disease index (DI) summarised the severity distribution observed. Examination of crown cross-sections was the most precise method for assessing crown cankers. The method was repeatable, though an 'assessor effect' was apparent. The disease generally had a random pattern although significant spatial correlations were detected for four out of the fifteen plots studied at the scales examined. A relationship between the coefficient of variation of the DI and the sample size was established, evaluated with experimental field data and exemplified for typical severity distributions. |
| قاعدة البيانات: | Supplemental Index |
| تدمد: | 09291873 15738469 |
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| DOI: | 10.1023/B:EJPP.0000015359.61910.3b |