Ramularia leaf spot is a major economic disease of barley caused by the dothidiomycete fungus Ramularia collo-cygni. The fungus has a complex life cycle which includes extensive late season spore release events and a seed-borne phase. Predicting disease epidemics during the growing season remains a difficult challenge. To better understand the interaction between spore movement and disease epidemics, spore samplers were set up in Germany (two sites over 4 years), Poland (seven sites over 2 years) and the UK (two sites over 9 years), where the disease has been observed. Spore concentrations were determined using a real time PCR assay, and meteorological data were obtained from co-located automatic stations. Spore release events were seen to peak in June on mainland Europe and July in the UK. The pattern of spore release was broadly similar across countries with earlier peaks in mainland Europe. A relationship was observed in the UK between July spore levels and disease in following winter barley crops. Rainfall and temperature were proposed as significant drivers of spore release in these months. The major environmental parameter associated with spore release across the two UK sites was crop surface wetness, although some site-specific interactions were noted for rainfall and wind movement. Regression analysis of spore patterns and disease epidemics indicates a relationship between spore levels 75–105 days pre harvest and final disease levels in UK winter barley crops. This relationship was not observed in spring barley. The implications on risk forecasts are discussed.

Ramularia叶斑病是大麦的一种主要经济病害，由双丝菌门真菌Ramularia collo-cygni引起。该真菌具有复杂的生命周期，包括广泛的晚季孢子释放事件和种子传播阶段。预测生长季节的疾病流行仍然是一个艰巨的挑战。为了更好地了解孢子运动与疾病流行之间的相互作用，在德国（4 年多的两个地点）、波兰（2 年多的 7 个地点）和英国（9 年多的两个地点）设立了孢子采样器，这些国家的疾病已被观察到。使用实时 PCR 测定确定孢子浓度，并从同一地点的自动站获得气象数据。欧洲大陆的孢子释放活动预计在 6 月达到顶峰，在英国则在 7 月达到顶峰。欧洲大陆孢子释放高峰较早的国家的孢子释放模式大致相似。在英国观察到七月孢子水平与随后的冬季大麦作物的疾病之间存在关系。降雨量和温度被认为是这几个月孢子释放的重要驱动因素。尽管在降雨和风运动方面注意到了一些特定地点的相互作用，但与英国两个地点的孢子释放相关的主要环境参数是作物表面湿度。孢子模式和疾病流行的回归分析表明，英国冬季大麦作物收获前 75-105 天的孢子水平与最终疾病水平之间存在关系。在春大麦中没有观察到这种关系。讨论了对风险预测的影响。