Fiume F, Fiume G
Sezione di Biologia, Fisiologia e Difesa, Istituto Sperimentale per l'Orticoltura (C.R.A.) Via Cavalleggeri 25, I-84098 Pontecagnano, Salerno, Italy.
Commun Agric Appl Biol Sci. 2005;70(3):157-68.
Research was carried out to evaluate the effectiveness of the biological control of two most important fungal diseases of lettuce (Lactuca sativa L.): 1) Botrytis Gray Mould caused by Botrytis cinerea Pers. ex Fr.; 2) Sclerotinia Drop caused by two pathogenic fungi, Sclerotinia sclerotiorum (Lib.) De Bary and/or Sclerotinia minorJagger. Biological control in lettuce was carried out: 1) using Coniothyrium minitans Campbell, an antagonist fungus that attacks and destroys sclerotia within the soil; 2) identifying lettuce genotypes showing less susceptibility or tolerance. The object of this research was to find control strategies to reduce chemical treatments. The use of resistant varieties is one of the most economical ways to control vegeTable diseases. The lettuce genotypes showing in preliminary trials the best behaviour to the sclerotial diseases were compared in a randomized complete block experiment design and replicated four times. Observations were carried out from February up to April registering the number of diseased plants and yield. The pathogens were isolated on PDA medium and identified. The isolates grown onto PDA plates, after incubation for 6 weeks, allowed obtaining sclerotia that were the target of C. minitans in biological control trials. In laboratory, in controlled conditions, 27 small plots (30 cm in diameter each) with disinfected soil were performed. In 18 plots 9 sclerotia were inoculated (per plot, three of each fungus) and in 9 plots of them a suspension of the antagonist fungus was added. Subsequently, three lettuce varieties were transplanted. For each variety were compared: 1) untreated plots; 2) treated plots with sclerotia only; 3) treated plots with sclerotia and C. minitans suspension. The number of diseased plants was recorded. According to symptom evaluation scale, ranged from 0 (no disease) up to 10 (100% necrotic leaves or dead plants) the plants were grouped into infection classes, calculating the McKinney index. In greenhouse trials, "LM 1307" genotype showed less significant susceptibility to Botrytis Gray Mould (0-2% of affected plants), while "Ninja" and "Charmy" showed 4-11% and 16-26% of diseased plants, respectively. The yields were 69.7, 62.7, 55.3 t/Ha, respectively. In laboratory tests, the McKinney index gave the following results: no disease in all untreated plants; 38.3, 54.2 and 89.2% in "LM 1307", "Ninja" and "Charmy" treated with sclerotia only, respectively; 2.5, 7.5 and 20.8% in "LM 1307", "Ninja" and "Charmy" treated with sclerotia and C. minitans, respectively. In conclusion, the less susceptibility of the genotypes to sclerotial diseases and the use of hyperparasites of sclerotia of phytopathogenic fungi exhibited best results.
开展了一项研究，以评估对生菜（Lactuca sativa L.）两种最重要真菌病害进行生物防治的效果：1）由灰葡萄孢（Botrytis cinerea Pers. ex Fr.）引起的灰霉病；2）由两种致病真菌，即核盘菌（Sclerotinia sclerotiorum (Lib.) De Bary）和/或小核盘菌（Sclerotinia minor Jagger）引起的菌核病。生菜的生物防治措施如下：1）使用小盾壳霉（Coniothyrium minitans Campbell），一种能攻击并破坏土壤中菌核的拮抗真菌；2）鉴定对病害敏感性较低或具有耐受性的生菜基因型。本研究的目的是寻找减少化学药剂处理的防治策略。使用抗性品种是防治蔬菜病害最经济的方法之一。在随机完全区组试验设计中，对在初步试验中表现出对菌核病最佳抗性的生菜基因型进行了比较，并重复4次。从2月至4月进行观察，记录发病植株数量和产量。病原菌在马铃薯葡萄糖琼脂（PDA）培养基上分离并鉴定。在PDA平板上培养6周后生长的分离菌可获得菌核，这些菌核是生物防治试验中小盾壳霉的作用对象。在实验室的可控条件下，准备了27个直径为30厘米、装有消毒土壤的小试验地。在18个试验地中接种了9个菌核（每个试验地接种每种真菌3个），并在其中9个试验地中添加了拮抗真菌的悬浮液。随后，移栽了3个生菜品种。对每个品种比较了以下情况：1）未处理的试验地；2）仅接种菌核的处理试验地；3）接种菌核并添加小盾壳霉悬浮液的处理试验地。记录发病植株数量。根据症状评估量表（范围从0（无病害）到10（100%坏死叶片或死亡植株）），将植株分为感染等级，计算麦金尼指数。在温室试验中，“LM 1307”基因型对灰霉病的敏感性较低（感病植株占0 - 2%），而“Ninja”和“Charmy”的感病植株分别占4 - 11%和16 - 26%。产量分别为69.7、62.7、55.3吨/公顷。在实验室试验中，麦金尼指数得出以下结果：所有未处理植株均无病害；仅接种菌核处理的“LM 1307”、“Ninja”和“Charmy”分别为38.3%、54.2%和89.2%；接种菌核并添加小盾壳霉处理的“LM 1307”、“Ninja”和“Charmy”分别为2.5%、7.5%和20.8%。总之，基因型对菌核病较低的敏感性以及使用植物病原真菌菌核的重寄生菌表现出了最佳效果。
