Ntahimpera N, Driever G F, Felts D, Morgan D P, Michailides T J
University of California, Davis, Kearney Agricultural Center, Parlier 93648.
Plant Dis. 2002 Mar;86(3):282-287. doi: 10.1094/PDIS.2002.86.3.282.
A study was conducted in four commercial pistachio orchards to monitor the presence and pattern of external contamination and latent infections of buds by Botryosphaeria dothidea between 1998 and 2000. Symptomless buds were sampled every 2 to 3 weeks and analyzed either by a washing/crushing method or by direct plating of split (half) or intact buds on lactic acid potato dextrose agar. The proportion of infected buds varied among orchards over time. Levels of latent infections were highest in February and March when they reached as much as 60% in orchards of Glenn and Yolo counties. This period corresponded to the months with the highest rainfall. Buds collected from orchards in Glenn and Yolo counties had, in general, higher incidence of infection than buds from San Joaquin and Merced counties. Buds became infected in June immediately after their formation. Infection incidence on basal segments of buds from male trees was approximately twice (19%) that of apical or middle segments (11%). Plating of split buds resulted in similar levels of incidence as the plating of intact buds. The number of B. dothidea propagules on bud surfaces varied over time and among orchards. In general, the number of propagules per bud was highest in February and March (approximately seven propagules per bud) when the rainfall amount was highest.
1998年至2000年间，在四个商业开心果园进行了一项研究，以监测葡萄座腔菌对外界污染的存在情况和模式以及芽的潜伏感染情况。每隔2至3周采集无症状芽，通过洗涤/压碎法或直接将劈开（一半）或完整的芽接种在乳酸马铃薯葡萄糖琼脂上进行分析。感染芽的比例随时间在不同果园中有所变化。潜伏感染水平在2月和3月最高，在格伦县和约洛县的果园中，此时潜伏感染率高达60%。这段时间对应降雨量最高的月份。一般来说，从格伦县和约洛县果园采集的芽比从圣华金县和默塞德县果园采集的芽感染发生率更高。芽在形成后立即于6月被感染。雄树芽基部的感染发生率约为顶端或中部芽的两倍（19%对11%）。劈开芽接种的感染发生率与完整芽接种的相似。芽表面葡萄座腔菌繁殖体的数量随时间和果园不同而变化。一般来说，当降雨量最高时，每个芽的繁殖体数量在2月和3月最高（每个芽约有7个繁殖体）。
