Anco D J, Madden L V, Ellis M A
The Ohio State University, Department of Plant Pathology, Ohio Agricultural Research and Development Center, 1680 Madison Avenue, Wooster, Ohio 44691.
Plant Dis. 2013 May;97(5):579-589. doi: 10.1094/PDIS-07-12-0666-RE.
Controlled-environment studies were conducted to examine effects of temperature (T) and wetness duration (W) on the sporulation rate of Phomopsis viticola on infected grape canes and to determine effects of interrupted wetness duration (IWD) on sporulation. A split-plot design was used to determine T and W effects, with T (5, 12, 15, 18, 20, 22, 25, 28, and 35°C) as the whole-plot and W (11, 23, 35, 47, and 71 h) as the subplot. Linear and nonlinear mixed models were fitted to the data. Lower and upper limits of sporulation were estimated to be 4 and 36°C, respectively, based on the modeling results, optimum sporulation was near 21°C, and sporulation increased monotonically with increasing wetness duration. Of the examined models, a generalization of the Analytis Beta model fit the data best, based on a collection of goodness-of-fit statistical criteria. To determine effects of IWD, a split-plot was used, with T (12, 15, and 20°C) as the whole-plot and IWD (0, 2, 4, 8, 12, and 24 h) as the subplot. Generally, sporulation declined with increasing IWD. An IWD of 8 h or more resulted in significantly and substantially less sporulation compared to the control (0 h IWD) (P < 0.01). Temporal patterns of spore density in the field were determined using a repeated-measures design, in which spore density and environmental data were measured in the vineyard during and following individual rain events over 3 years. The developed model from the controlled-environment study, coupled with a time-of-season weight function and a dispersal index (based on total rain per rain episode), predicted the trend in spore density over time reasonably well, although the total magnitude of spore density could not be predicted because the density of lesions was not known. Results can be used for improving the accuracy of a disease warning system that currently only considers infection of grapes by P. viticola.
开展了控制环境研究，以考察温度（T）和湿润持续时间（W）对感染葡萄茎上葡萄生拟茎点霉产孢率的影响，并确定间断湿润持续时间（IWD）对产孢的影响。采用裂区设计来确定温度和湿润持续时间的影响，将温度（5、12、15、18、20、22、25、28和35℃）作为主区，湿润持续时间（11、23、35、47和71小时）作为副区。对数据拟合了线性和非线性混合模型。根据建模结果，估计产孢的下限和上限分别为4℃和36℃，最佳产孢温度接近21℃，且产孢随湿润持续时间的增加而单调增加。在所考察的模型中，基于一系列拟合优度统计标准，Analytis Beta模型的推广形式对数据拟合最佳。为了确定间断湿润持续时间的影响，采用裂区设计，将温度（12、15和20℃）作为主区，间断湿润持续时间（0、2、4、8、12和24小时）作为副区。一般来说，产孢随间断湿润持续时间的增加而下降。与对照（间断湿润持续时间为0小时）相比，间断湿润持续时间为8小时或更长时间会导致产孢显著减少（P < 0.01）。利用重复测量设计确定了田间孢子密度的时间模式，在3年期间，在每次降雨事件期间及之后在葡萄园测量孢子密度和环境数据。尽管由于病斑密度未知无法预测孢子密度的总量，但控制环境研究中开发的模型，结合季节时间权重函数和扩散指数（基于每次降雨事件的总降雨量），能较好地预测孢子密度随时间的变化趋势。研究结果可用于提高目前仅考虑葡萄被葡萄生拟茎点霉感染的病害预警系统的准确性。
