Bock Clive H, Wood Bruce W, Gottwald Tim R
United States Department of Agriculture-Agricultural Research Service (USDA-ARS)-Southeastern Fruit and Tree Nut Research Laboratory, Byron, GA 31008.
USDA-ARS-United States Horticultural Research Laboratory, Ft. Pierce, FL 34945.
Plant Dis. 2013 May;97(5):675-684. doi: 10.1094/PDIS-07-12-0642-RE.
Pecan scab is caused by the fungus Fusicladium effusum, and is the most destructive disease of pecan in the United States. Accurate and reliable disease assessments are needed to ensure that data provide a measure of actual disease intensity. The Horsfall-Barratt (H-B) category scale and its derivatives are commonly used to assess disease. Estimates using the H-B scale were compared with nearest percent estimate (NPEs) for rating disease severity of pecan scab on valves of fruit. Both inexperienced and experienced raters were included in the experiment. Lin's concordance correlation showed that agreement using NPEs was variable (ρ = 0.57 to 0.96), whereas estimates of disease severity using the H-B scale had similar agreement among most raters (ρ = 0.59 to 0.98). Converted values of NPEs to the H-B midpoints (NPEH-B) also provided a similar range (ρ = 0.61 to 0.96). Neither experienced nor inexperienced raters were consistently better using any of the three methods. Bootstrap analysis indicated that, among experienced raters, precision (r) and agreement (ρ) were often reduced when using the H-B scale compared with NPEs. There was no consistent effect of converting NPEs to NPEH-B midpoint values compared with actual H-B values. Inter-rater reliability using the H-B scale was never better than NPEs. Bootstrap analysis indicated no difference in the length of time needed to assess disease but regression analysis suggested that raters who were inherently fast in assessing disease with NPEs were often slower when using the H-B scale; conversely, raters who were slow assessing with NPEs were often faster when using the H-B scale. Thus, there appears to be no advantage in accuracy or reliability or reduction in time when inexperienced or experienced raters used a category rating scale to assess pecan scab.
山核桃疮痂病由真菌Fusicladium effusum引起，是美国山核桃最具毁灭性的病害。需要准确可靠的病害评估，以确保数据能衡量实际病害强度。常用霍斯福尔-巴拉特（H-B）分类量表及其衍生量表来评估病害。将使用H-B量表的估计值与用于评定果实果壳上山核桃疮痂病病害严重程度的最接近百分比估计值（NPEs）进行比较。实验中纳入了经验不足和经验丰富的评级人员。林氏一致性相关性表明，使用NPEs的一致性存在差异（ρ = 0.57至0.96），而使用H-B量表估计病害严重程度在大多数评级人员中具有相似的一致性（ρ = 0.59至0.98）。将NPEs转换为H-B中点值（NPEH-B）也提供了类似的范围（ρ = 0.61至0.96）。经验丰富和经验不足的评级人员使用这三种方法中的任何一种都没有始终表现得更好。自助法分析表明，在经验丰富的评级人员中，与NPEs相比，使用H-B量表时精度（r）和一致性（ρ）通常会降低。将NPEs转换为NPEH-B中点值与实际H-B值相比没有一致的影响。使用H-B量表的评分者间信度从未优于NPEs。自助法分析表明评估病害所需时间没有差异，但回归分析表明，本质上使用NPEs评估病害速度快的评级人员使用H-B量表时往往较慢；相反，使用NPEs评估速度慢的评级人员使用H-B量表时往往较快。因此，经验不足或经验丰富的评级人员使用分类评级量表评估山核桃疮痂病时，在准确性、可靠性或时间减少方面似乎没有优势。
