Wright E R, Rivera M C, Esperón J, Cheheid A, Rodríguez Codazzi A
Fitopatología. Facultad de Agronomía, Universidad de Buenos Aries, Av. San Martín 4453 (1417), Buenos Aires, Argentina.
Plant Dis. 2004 Dec;88(12):1383. doi: 10.1094/PDIS.2004.88.12.1383B.
Disease symptoms have been observed since October 1997 on highbush blueberry (Vaccinium corymbosum L.) cvs. Georgia Gem, O'Neal, and Sharpblue cultivated in Buenos Aires. Lesions were observed on recently planted, as well as mature plants, in commercial fields. Circular-to-irregular, light brown-to-gray leaf spots with brownish red borders, initially 3 to 7 mm in diameter, enlarged and coalesced. Blight developed on twigs. Reddish circular spots appeared on stems, developing small cankers. Dark sunken lesions were observed on attached ripening berries. During December 2002, postharvest fruit rot was noted. Small pieces of diseased leaves, twigs, stems, and fruits were surface sterilized with 0.2% NaOCl, plated on 2% potato dextrose agar (pH 7), and incubated at 20 ± 3°C. Symptomatic fruits were placed in plastic trays in humid chambers. In all cases, olive mycelium developed after 3 days with septate hyphae and abundant ovoid and obclavate muriformly septate conidia. The isolate obtained from diseased leaves of cv. O'Neal was used to test pathogenicity on micropropagated potted plants of 20-cm height and ripe fruits contained in plastic trays. Both plants and fruits belonged to cv. O'Neal. A suspension of 2 × 10 conidia per ml was sprayed on needle-punctured young stems, fully expanded leaves, and mature fruits. Plants and trays were covered with polyethylene bags and kept at 24 ± 3°C under fluorescent light (12-hr photoperiod). The bags were removed after 72 hr. Symptoms appeared after 3 days on fruits and 8 days on leaves and stems. Controls remained symptomless. The inoculated pathogen was recovered from diseased organs and identified as Alternaria tenuissima (Kunze:Fr.) Wiltshire (1). To our knowledge, this is the first report on the presence of A. tenuissima affecting blueberry crops in Argentina. Reference: (1) E. G. Simmons. Mycotaxon 70:325, 1999.
自1997年10月起，在布宜诺斯艾利斯种植的高丛蓝莓（Vaccinium corymbosum L.）品种Georgia Gem、O'Neal和Sharpblue上观察到病害症状。在商业种植园中，新种植的以及成熟植株上均观察到病斑。叶片上出现圆形至不规则形、浅褐色至灰色的叶斑，边缘呈褐红色，最初直径为3至7毫米，后扩大并融合。嫩枝上发生枯萎病。茎上出现红色圆形斑点，发展为小溃疡。在附着的成熟浆果上观察到深色凹陷病斑。2002年12月，发现采后果实腐烂。将病叶、嫩枝、茎和果实的小块用0.2%次氯酸钠进行表面消毒，接种在2%马铃薯葡萄糖琼脂（pH 7）上，于20±3°C培养。有症状的果实置于塑料托盘中，放在湿度箱中。在所有情况下，3天后均长出橄榄色菌丝体，有分隔的菌丝，以及大量卵形和棍棒形、具多隔的分生孢子。从O'Neal品种病叶上分离得到的菌株用于对20厘米高的微繁殖盆栽植株和塑料托盘中的成熟果实进行致病性测试。植株和果实均属于O'Neal品种。将每毫升含2×10个分生孢子的悬浮液喷洒在针刺的嫩茎、完全展开的叶片和成熟果实上。植株和托盘用聚乙烯袋覆盖，置于荧光灯下（光周期12小时），温度保持在24±3°C。72小时后取下袋子。果实3天后出现症状，叶片和茎8天后出现症状。对照植株无症状。从患病器官中重新分离出接种的病原菌，鉴定为细链格孢（Alternaria tenuissima (Kunze:Fr.) Wiltshire）（1）。据我们所知，这是阿根廷首次报道细链格孢侵染蓝莓作物。参考文献：（1）E. G. Simmons. Mycotaxon 70:325, 1999。
