abstract The downy mildew of basil, which is caused by Peronospora belbahrii, is one of the most devastating basil diseases throughout the world, and management programmes with a limited use of fungicides are necessary to control it. In order to develop efficient integrated disease management programmes, the efficacy of alternative products (calcium oxide, zeolite, orange oil with ascorbic acid, potassium phosphites and bicarbonate), applied in different spray programmes in trials carried out under artificial and natural infestations with the pathogen, has been tested. Various combinations of the treatments were chosen, on the basis of the efficacy of the single products, for further testing in experiments carried out in the presence of natural pathogen infestation and under a reduced crop density. The effect of the tested programmes on downy mildew severity (% of affected leaf area), disease development (AUDPC) and yield (fresh weight of plants) was evaluated. Calcium oxide, K-phosphite and orange oil with ascorbic acid generally provided the most consistent disease control (58%, 40% and 26% efficacy, respectively), when used alone under severe disease pressure, compared to the inoculated control. Spray programmes based on calcium oxide, applied 2 to 4 times, in succession to one application of azoxystrobin, and under a reduced crop density, were the most efficient treatment in the presence of a natural infestation by the pathogen; this IPM programme reduced downy severity as much as 80%, providing the same effect as a conventional chemical programme based on the alternation of azoxystrobin, fluopicolide + propamocarb and mandipropamid.

中文翻译：

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罗勒霜霉病综合治理

摘要 罗勒霜霉病由 Peronospora belbahrii 引起，是全世界最具破坏性的罗勒病害之一，需要限制使用杀菌剂的管理计划来控制它。为了制定有效的综合疾病管理计划，替代产品（氧化钙、沸石、含抗坏血酸的橙油、亚磷酸钾和碳酸氢盐）的功效，在人工和自然感染病原体下进行的试验中应用于不同的喷雾程序，经过测试。根据单一产品的功效，选择了各种处理组合，以便在存在天然病原体侵染和降低作物密度的情况下进行的实验中进行进一步测试。评估了测试程序对霜霉病严重程度（受影响叶面积的百分比）、疾病发展 (AUDPC) 和产量（植物鲜重）的影响。与接种对照相比，在严重疾病压力下单独使用氧化钙、亚磷酸钾和含有抗坏血酸的橙油通常可提供最一致的疾病控制（分别为 58%、40% 和 26% 的功效）。以氧化钙为基础的喷洒程序，在施用一次嘧菌酯之后施用 2 至 4 次，并在降低作物密度的情况下，在病原体自然侵染的情况下是最有效的处理方法；该 IPM 程序将严重程度降低了 80%，提供与基于嘧菌酯、氟啶虫胺 + 霜霉威和茚虫胺交替的传统化学程序相同的效果。