Wang L, Vincelli P
Department of Plant Pathology, University of Kentucky, Lexington 40546-0091.
Plant Dis. 1997 Jun;81(6):695. doi: 10.1094/PDIS.1997.81.6.695D.
During a study of apothecial dynamics of Sclerotinia trifoliorum at the University of Kentucky Spindletop Farm at Lexington, an apothecium with small black patches on the surface of the hymenium was found. The affected apothecium was incubated in a moist chamber at room temperature. After 3 days, white, cottony mycelium was observed on the surface of the hymenium; pycnidia formed in the mycelium and around the stipe of the apothecium several days later. The apothecium eventually decayed and shrunk. Pycnidia measured 168 to 520 μm (mean 311 μm). Pycnidiospores were dark brown en masse; they were ovoid to ellipsoid, measuring 3.1 to 8.2 μm (mean 6.0 μm) in length and 3.1 to 4.1 μm (mean 3.7 μm) in width, and were faintly verrucose. Fresh sclerotia of S. trifoliorum were produced in vitro and then inoculated with pycnidiospores produced on potato dextrose agar. Inoculated sclerotia were incubated in a moist chamber at room temperature. After 7 to 10 days, inoculated sclerotia shriveled and decayed, pycnidia formed on their surfaces, and the same fungus was isolated. The fungus was identified as Coniothyrium minitans Campbell. Among 58 apothecia examined in the field on 1 November, three were apparently parasitized; pycnidia developed on one of these following a 3-day incubation. Weather conditions during the preceding 2 weeks had been generally humid with above-normal temperatures (daily mean air temperature range and interquartile range were 4.0 to 20.0 and 8.9 to 16.1°C, respectively), which may have favored activity of the mycoparasite. C. minitans was reported by Campbell (1) in California on sclerotia formed in cultures of Sclerotinia sclerotiorum. It causes decay of sclerotia of several Sclerotinia spp., some Botrytis spp., and Sclerotium cepivorum in soil. Consequently, it may have considerable biological control potential. It has been recorded in 29 countries and on all continents except South America (2). The fungus previously has been isolated from only sclerotia or, in a few instances, directly from soil. This is the first report on C. minitans parasitic on apothecia collected from the field. References: (1) W. A. Campbell. Mycologia 39:190, 1947. (2) C. Sandys-Winsch et al. Mycol. Res. 97:1175, 1993.
在肯塔基大学列克星敦分校斯平德托普农场对三叶草核盘菌子囊盘动态进行研究期间，发现一个子囊盘的子实层表面有小黑斑。将受影响的子囊盘在室温下的保湿培养箱中培养。3天后，在子实层表面观察到白色棉絮状菌丝体；几天后，在菌丝体中和子囊盘菌柄周围形成了分生孢子器。子囊盘最终腐烂并萎缩。分生孢子器大小为168至520μm（平均311μm）。分生孢子成堆时呈深褐色；呈卵形至椭圆形，长3.1至8.2μm（平均6.0μm），宽3.1至4.1μm（平均3.7μm），表面有微弱疣状突起。在体外产生新鲜的三叶草核盘菌菌核，然后接种在马铃薯葡萄糖琼脂上产生的分生孢子。接种后的菌核在室温下的保湿培养箱中培养。7至10天后，接种的菌核皱缩并腐烂，表面形成分生孢子器，且分离出了相同的真菌。该真菌被鉴定为小盾壳霉坎贝尔变种。11月1日在田间检查的58个子囊盘中，有3个明显被寄生；其中一个在培养3天后产生了分生孢子器。前两周的天气条件总体湿润，温度高于正常水平（日平均气温范围和四分位间距分别为4.0至20.0和8.9至16.1°C），这可能有利于这种真菌寄生菌的活动。坎贝尔（1）在加利福尼亚州报道小盾壳霉寄生在核盘菌培养物中形成的菌核上。它会导致土壤中几种核盘菌属、一些葡萄孢属和洋葱核盘菌的菌核腐烂。因此，它可能具有相当大的生物防治潜力。它已在29个国家被记录，除南美洲外各大洲均有分布（2）。此前该真菌仅从菌核中分离得到，或在少数情况下直接从土壤中分离得到。这是关于小盾壳霉寄生在田间采集的子囊盘上的首次报道。参考文献：（1）W. A. 坎贝尔。《真菌学》39:190，1947年。（2）C. 桑迪斯 - 温施等人。《真菌研究》97:1175，1993年。
