McManus P S
Department of Plant Pathology, University of Wisconsin, Madison 53706.
Plant Dis. 1998 Mar;82(3):350. doi: 10.1094/PDIS.1998.82.3.350A.
Phyllosticta vaccinii Earle causes early rot of cranberry (Vaccinium macrocarpon Aiton) and previously was reported in fruit and leaves from Massachusetts and New Jersey, but not Wisconsin or Washington (2). This fungus previously was introduced into Wisconsin, apparently on planting stock, but did not persist in the field (2). In the present study, rotted fruit were collected in central Wisconsin in September 1997 from research plots adjacent to a commercial planting that had been started from field cuttings from New Jersey. P. vaccinii was isolated from 12 of 31 symptomatic berries, and its identity was verified by cultural and morphological characteristics (3). P. vaccinii was not isolated from rotted fruit from five other sites in central and northern Wisconsin. In three separate experiments, 10 to 25 cv. Stevens or Searles cranberry fruit were punctured with a needle, inoculated with 2 to 4 × 10 conidia from sporulating cultures of P. vaccinii, and incubated at 28°C in a moist chamber. After 5 to 14 days, soft, watery spots developed at the inoculation point on 8 to 22% of the fruit in different experiments, and P. vaccinii was reisolated from the lesions. Fruit that were punctured but not inoculated neither developed symptoms nor yielded P. vaccinii. Previous attempts at fulfilling Koch's postulates by inoculating mature fruit were unsuccessful (1). P. vaccinii is one of approximately 15 species of fungi involved in the cranberry fruit rot complex in the eastern U.S. where fungicides are applied to greater than 95% of cranberry acreage, usually three times per year, primarily to control preharvest fruit rots. In Wisconsin, however, preharvest fruit rots are insignificant; less than 25% of the acreage is treated with fungicides. The occurrence of early rot in Wisconsin and the threat of introducing pathogens on cranberry cuttings are troublesome in light of the Food Quality Protection Act of 1996, which threatens registration of fungicides used to control cranberry fruit rots. References: (1) D. M. Boone. Pages 35-36 in: Compendium of Blueberry and Cranberry Diseases. F. L. Caruso and D. C. Ramsdell, eds. American Phytopathological Society, 1995. (2) G. J. Weidemann and D. M. Boone. Plant Dis. 67:1090, 1983. (3) G. J. Weidemann et al. Mycologia 74:59, 1982.
越橘叶点霉（Phyllosticta vaccinii Earle）会引发蔓越莓（Vaccinium macrocarpon Aiton）早期腐烂，此前在马萨诸塞州和新泽西州的果实及叶片中被发现，但在威斯康星州或华盛顿州未出现过（2）。这种真菌此前被引入威斯康星州，显然是通过种植材料带入的，但未在田间持续存在（2）。在本研究中，1997年9月在威斯康星州中部从与一片商业种植园相邻的研究地块收集到腐烂果实，该商业种植园是由来自新泽西州的田间插条培育而成。从31个有症状的浆果中的12个分离出了越橘叶点霉，其身份通过培养和形态特征得以验证（3）。在威斯康星州中部和北部的其他五个地点的腐烂果实中未分离到越橘叶点霉。在三个独立实验中，用针穿刺10至25个史蒂文斯（cv. Stevens）或塞尔尔斯（Searles）品种的蔓越莓果实，接种来自越橘叶点霉产孢培养物的2至4×10个分生孢子，并在28°C的潮湿培养箱中培养。5至14天后，在不同实验中，8%至22%的果实接种点出现软腐、水渍状斑点，且从这些病斑中再次分离出了越橘叶点霉。穿刺但未接种的果实既未出现症状也未分离到越橘叶点霉。此前通过接种成熟果实来完成科赫法则的尝试未成功（1）。越橘叶点霉是美国东部参与蔓越莓果实腐烂复合体的约15种真菌之一，在美国东部，超过95%的蔓越莓种植面积使用杀菌剂，通常每年三次，主要用于控制收获前的果实腐烂。然而，在威斯康星州，收获前的果实腐烂并不严重；不到25%的种植面积使用杀菌剂进行处理。鉴于1996年的《食品质量保护法》对用于控制蔓越莓果实腐烂的杀菌剂注册构成威胁，威斯康星州早期腐烂的出现以及蔓越莓插条引入病原体的威胁令人担忧。参考文献：（1）D. M. 布恩。载于：《蓝莓和蔓越莓病害汇编》。F. L. 卡鲁索和D. C. 拉姆齐德尔编。美国植物病理学会，1995年，第35 - 36页。（2）G. J. 魏德曼和D. M. 布恩。《植物病害》67:1090，1983年。（3）G. J. 魏德曼等人。《真菌学》74:59，1982年。
