Phytopathology. 2004 Dec;94(12):1342-9. doi: 10.1094/PHYTO.2004.94.12.1342.
ABSTRACT Rain splash dispersal of Gibberella zeae, causal agent of Fusarium head blight of wheat, was investigated in field studies in Ohio between 2001 and 2003. Samplers placed at 0, 30, and 100 cm above the soil surface were used to collect rain splash in wheat fields with maize residue on the surface and fields with G. zeae-infested maize kernels. Rain splash was collected during separate rain episodes throughout the wheat-growing seasons. Aliquots of splashed rain were transferred to petri dishes containing Komada's selective medium, and G. zeae was identified based on colony and spore morphology. Dispersed spores were measured in CFU/ml. Intensity of splashed rain was highest at 100 cm and ranged from 0.2 to 10.2 mm h(-1), depending on incident rain intensity and sampler height. Spores were recovered from splash samples at all heights in both locations for all sampled rain events. Both macroconidia and ascospores were found based on microscopic examination of random samples of splashed rain. Spore density and spore flux density per rain episode ranged from 0.4 to 40.9 CFU cm(-2) and 0.4 to 84.8 CFU cm(-2) h(-1), respectively. Spore flux density was higher in fields with G. zeae-infested maize kernels than in fields with maize debris, and generally was higher at 0 and 30 cm than at 100 cm at both locations. However, on average, spore flux density was only 30% lower at 100 cm (height of wheat spikes) than at the other heights. The log of spore flux density was linearly related to the log of splashed rain intensity and the log of incident rain intensity. The regression slopes were not significantly affected by year, location, height, and their interactions, but the intercepts were significantly affected by both sampler height and location. Thus, our results show that spores of G. zeae were consistently splash dispersed to spike heights within wheat canopies, and splashed rain intensity and spore flux density could be predicted based on incident rain intensity in order to estimate inoculum dispersal within the wheat canopy.
2001 年至 2003 年，在俄亥俄州的田间研究中，调查了导致小麦赤霉病的禾谷镰刀菌的雨水飞溅扩散。在表面有玉米残茬的小麦田和感染禾谷镰刀菌的玉米穗的小麦田，使用放置在距地面 0、30 和 100cm 处的采样器收集雨水飞溅。在整个小麦生长季节，通过单独的降雨事件收集雨水飞溅。将飞溅雨水的等分试样转移到含有 Komada 选择性培养基的培养皿中，并根据菌落和孢子形态鉴定禾谷镰刀菌。以 CFU/ml 计测量分散的孢子。溅起的雨强度在 100cm 处最高，范围为 0.2 至 10.2mm/h，具体取决于降雨强度和采样器高度。在两个地点的所有采样降雨事件中，在所有高度都从飞溅样本中回收了孢子。根据对飞溅雨水随机样本的显微镜检查，发现了大孢子和分生孢子囊。孢子密度和每降雨事件的孢子通量密度范围分别为 0.4 至 40.9CFU/cm2和 0.4 至 84.8CFU/cm2/h。在有感染禾谷镰刀菌的玉米穗的田地中，孢子通量密度高于有玉米碎屑的田地，并且通常在两个地点的 0 和 30cm 处高于 100cm。然而，平均而言，在 100cm（小麦穗高度）处的孢子通量密度仅比其他高度低 30%。孢子通量密度的对数与飞溅雨强度的对数和降雨强度的对数呈线性关系。回归斜率不受年份、地点、高度及其相互作用的显著影响，但截距受采样器高度和位置的显著影响。因此，我们的研究结果表明，禾谷镰刀菌的孢子会持续飞溅到小麦冠层内的穗高，并且可以根据降雨强度来预测飞溅雨强度和孢子通量密度，以便估计小麦冠层内的接种体传播。
