Latorre B A, Besoain X
Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica, Casilla 306-22, Santiago, Chile.
Facultad de Agronomía, Universidad Católica de Valparaíso, Casilla 4-D, Quillota, Chile.
Plant Dis. 2002 Jun;86(6):694. doi: 10.1094/PDIS.2002.86.6.694B.
Severe outbreaks of leaf mold, affecting as much as 100% of the plants, have occurred in greenhouse tomatoes (Lycopersicon esculentum Mill.) in the V Region in the central zone of Chile (32°50' to 33°10' latitude south) during the past 2 years. Symptoms consisted of yellow spherical to elongated leaf spots, first noticeable on the upper surface of older leaves, followed by leaf necrosis and defoliation. Invariably, an olive green-to-gray leaf mold developed on the under surface of the spots. No symptoms were observed on fruits and rarely occurred on petioles and stems. Isolation on acidified potato dextrose agar (APDA) consistently yielded dark green colonies of a very slow growing fungus that was identified as Fulvia fulva (Cooke) Cif. (=Cladosporium fulvum Cooke) (1). Identification was based on the presence of a dark septate mycelium, ovoid to ellipsoid conidia, usually one or two cells, pale or slightly yellow, 11 × 40 μm long, and the presence of mostly unbranched conidiophores that were broader at the tip. Conidia were produced in short chains, and a very distinctive hilum was always observed (1,3). Thin sections of leaf lesions revealed the presence of inter- and intracellular mycelia that protruded through the stomata forming a small stroma in the stomatal cavity from which the conidiophores were produced. Leaf inoculations of tomato cvs. Fortaleza and Cal-Ace with a mixture of mycelia and conidia from isolates Fv1 and Fv2 on APDA (approximately 10 propagules per ml) and with three different samples of conidia (10 conidia per ml) obtained directly from actively growing lesions resulted in the development of pale to dark yellow spots after 12 to 15 days of incubation under greenhouse conditions (temperatures ranging from 9 to 30°C). Leaf spots developed mainly on inoculated leaflets, but occasionally symptoms were obtained on other leaflets on the same leaf. Reisolations made from samples of artificially inoculated leaves always yielded F. fulvia on APDA. Therefore, it was concluded that F. fulvia was the cause of the severe outbreaks of tomato leaf mold found in central Chile. Previously, it has been reported in northern Chile (I Region approximately 2,000 km away) (2). To our knowledge, this is the first confirmed report of leaf mold on greenhouse tomato in central Chile. References: (1) P. Holliday and J. L. Mulder. Fulvia fulva. No. 487 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1976. (2) F. Mujica and C. Vergara. Flora Fungosa Chilena. 2nd ed. Universidad de Chile, Facultad de Agronomía, Santiago, Chile, 1980. (3) A. F. Sherf and A. A. Macnab. Vegetable Diseases and Their Control, 2nd ed. John Wiley and Sons, New York, 1986.
在过去两年里，智利中部地区（南纬32°50′至33°10′）的第五大区，温室番茄（Lycopersicon esculentum Mill.）爆发了严重的叶霉病，受影响植株高达100%。症状表现为黄色球形至椭圆形叶斑，最初在老叶上表面较为明显，随后出现叶片坏死和落叶。斑点下表面总会形成橄榄绿至灰色的叶霉。果实上未观察到症状，叶柄和茎上也很少出现。在酸化马铃薯葡萄糖琼脂（APDA）上分离培养，始终能得到一种生长极为缓慢的深绿色菌落真菌，鉴定为富氏叶霉（Fulvia fulva (Cooke) Cif.）（=fulvum枝孢菌Cooke）（1）。鉴定依据是存在深色分隔菌丝体、卵形至椭圆形分生孢子（通常一至两个细胞，浅色或略带黄色，长11×40μm），以及大多不分枝且顶端较宽的分生孢子梗。分生孢子呈短链状产生，总能观察到一个非常独特的脐点（1,3）。叶片病斑的薄片显示存在细胞间和细胞内菌丝体，这些菌丝体通过气孔突出，在气孔腔内形成一个小基质，分生孢子梗由此产生。用分离株Fv1和Fv2在APDA上的菌丝体和分生孢子混合物（约每毫升10个繁殖体）以及直接从活跃生长的病斑获得的三种不同分生孢子样品（每毫升10个分生孢子）对番茄品种Fortaleza和Cal - Ace进行叶片接种，在温室条件下（温度9至30°C）培养12至15天后，出现了从浅色到深色的黄斑。叶斑主要出现在接种的小叶上，但同一叶片上的其他小叶偶尔也会出现症状。从人工接种叶片的样品中重新分离，在APDA上始终能得到富氏叶霉。因此，得出结论：富氏叶霉是智利中部发现的番茄严重叶霉病爆发的病因。此前，在智利北部（第一大区，距离约2000公里）已有该病报道（2）。据我们所知，这是智利中部温室番茄叶霉病的首次确诊报告。参考文献：（1）P. Holliday和J. L. Mulder。富氏叶霉。载于《病原真菌和细菌描述》第487号。英国皇家植物园真菌研究所，英国萨里郡邱园，1976年。（2）F. Mujica和C. Vergara。《智利真菌志》第二版。智利大学农学院，智利圣地亚哥，1980年。（3）A. F. Sherf和A. A. Macnab。《蔬菜病害及其防治》第二版。约翰·威利父子公司，纽约，1986年。
