Phytopathology. 1998 Feb;88(2):122-8. doi: 10.1094/PHYTO.1998.88.2.122.
ABSTRACT Relationships between environmental factors and release of ascospores of Anisogramma anomala, the causal agent of eastern filbert blight, were examined in four European hazelnut (Corylus avellana) orchards during a 2-year period. In each orchard, Burkhard volumetric spore traps and automated weather-monitoring equipment were deployed for 12-week periods beginning at budbreak, when hazelnut becomes susceptible to infection. Ascospores of A. anomala were released when stromata on the surface of hazelnut branches were wet from rain but not from dew. Release of ascospores ceased after branch surfaces dried. The duration of free moisture on branch surfaces regulated the initiation and rate of ascospore release, but no significant effects of temperature, relative humidity, wind, or light on ascospore release were apparent. Most (>90%) ascospores were captured during precipitation events that exceeded 20 h in duration, which represented about 10% of the total precipitation events each season. Quantitative relationships between the hourly capture of A. anomala ascospores and hours since the beginning of a precipitation event were developed. With the onset of precipitation, the hourly rate of ascospore capture increased until the fifth hour of rain, remained relatively constant between the fifth and twelfth hours, and then declined gradually. During the 12-week spore-trapping periods, the likelihood and rates of ascospore release associated with precipitation were highest at budbreak and then declined through April and May until early June, when the reserve of ascospores in the perithecia was depleted. Large numbers of ascospores were captured in the volumetric spore traps, indicating that ascospores may be commonly dispersed long distances on air currents as well as locally by splash dispersal within the canopy, as reported previously. The results indicate that monitoring seasonal precipitation patterns may be useful for estimating the quantity and temporal distribution of airborne inoculum during the period that the host is susceptible to infection.
在两年的时间里，研究人员在四个欧洲榛子（ Corylus avellana ）果园中检查了环境因素与东方榛枯萎病病原菌（ Anisogramma anomala ）分生孢子释放之间的关系。在每个果园中，在芽开始萌动、榛子易受感染时，使用 Burkhard 容量孢子陷阱和自动气象监测设备进行了为期 12 周的监测。当榛子树枝表面的菌核因雨水而不是露水而湿润时，就会释放出 A. anomala 分生孢子。当树枝表面干燥后，分生孢子的释放就会停止。树枝表面自由水分的持续时间调节了分生孢子释放的开始和速率，但温度、相对湿度、风和光对分生孢子释放没有明显影响。超过 20 小时的降水事件中捕获了大部分（>90%）分生孢子，这约占每个季节总降水事件的 10%。建立了 A. anomala 分生孢子每小时捕获量与降水开始后小时数之间的定量关系。随着降水的开始，每小时分生孢子的捕获率增加，直到降雨的第五小时，在第五到第十二小时之间相对稳定，然后逐渐下降。在 12 周的孢子捕捉期间，与降水相关的分生孢子释放的可能性和速率在芽萌动时最高，然后在 4 月和 5 月下降，直到 6 月初，子囊壳中的分生孢子储备耗尽。大量的分生孢子被容量孢子陷阱捕获，这表明分生孢子可能会在气流中长距离地扩散，也可能像以前报道的那样，在树冠内通过飞溅扩散而局部扩散。结果表明，监测季节性降水模式可能有助于估计宿主易受感染期间空气中接种体的数量和时间分布。
