Cucumber powdery mildew disease caused by Podosphaera xanthii (Castagne) U. Braun & Shishkoff severe disease-causing yield losses worldwide. This research study was conducted to evaluate the efficacy of the tested bio-agents, Trichoderma harzianum, T. viride, Bacillus subtilis, Paenibacillus polymyxa, and Serratia marcescens, as well as the fungicide score (Difenoconazole), on cucumber infected with P. xanthii, in vitro and under greenhouse conditions. Results indicated that culture filtrate of the tested bio-agents and the fungicide (control) significantly reduced P. xanthii conidial germination in vitro; the reduction percentage ranged between 91.17 and 76.06%. Also, score recorded the highest reduction percentage (97.19%). All treatments significantly decreased the disease severity and area under disease progress curve (AUDPC) post spraying the bio-agents on cucumber plants under greenhouse conditions. Score followed by B. subtilis significantly decreased disease severity percentage (67.33 and 65.38%, respectively) and AUDPC (322.84 and 342.06) than the untreated control (988.13 AUDPC). Additionally, treated cucumber plants showed a significant increase in plant growth parameters (plant height, total chlorophyll, fresh, and dry weight) and yield parameters (fruit number/plant and fruit weight/plant) as well the activity of defense-related enzymes, i.e., peroxidase (PO) and polyphenol oxidase (PPO), and total phenols content (TPC) compared to the untreated plants.

中文翻译：

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温室条件下黄瓜白粉病（Podosphaera xanthii）（Castagne）的生物防治。

由Podosphaera xanthii（Castagne）U. Braun＆Shishkoff引起的黄瓜白粉病在世界范围内引起严重的致病产量损失。这项研究旨在评估被测生物制剂，哈茨木霉，拟南芥，枯草芽孢杆菌，多粘芽孢杆菌和粘质粘质沙雷氏菌的功效，以及杀菌剂评分（Difenoconazole）对感染黄腐病菌黄瓜的功效。 ，体外和温室条件下。结果表明，所测试的生物制剂和杀菌剂（对照）的培养滤液在体外显着减少了黄腐病菌的分生孢子萌发。减少比例在91.17至76.06％之间。此外，得分录得最高减少率（97.19％）。在温室条件下，向黄瓜植株喷洒生物制剂后，所有处理均显着降低了疾病的严重程度和病情进展曲线下的面积（AUDPC）。得分紧随其后的是枯草芽孢杆菌，与未治疗的对照组（988.13 AUDPC）相比，疾病严重程度百分比（分别为67.33和65.38％）和AUDPC（322.84和342.06）明显降低。此外，处理过的黄瓜植株在植物生长参数（植株高度，总叶绿素，鲜重和干重）和产量参数（果实数量/植物和果实重量/植物）以及防御相关酶的活性方面均显着提高，与未经处理的植物相比，即过氧化物酶（PO）和多酚氧化酶（PPO）以及总酚含量（TPC）。与未治疗的对照组（988.13 AUDPC）相比，枯草杆菌显着降低了疾病严重程度百分比（分别为67.33和65.38％）和AUDPC（322.84和342.06）。此外，处理过的黄瓜植株在植物生长参数（植株高度，总叶绿素，鲜重和干重）和产量参数（果实数量/植物和果实重量/植物）以及防御相关酶的活性方面均显着提高，与未经处理的植物相比，即过氧化物酶（PO）和多酚氧化酶（PPO）以及总酚含量（TPC）。与未治疗的对照组（988.13 AUDPC）相比，枯草杆菌显着降低了疾病严重程度百分比（分别为67.33和65.38％）和AUDPC（322.84和342.06）。此外，处理过的黄瓜植株在植物生长参数（植株高度，总叶绿素，鲜重和干重）和产量参数（果实数量/植物和果实重量/植物）以及防御相关酶的活性方面均显着提高，与未经处理的植物相比，即过氧化物酶（PO）和多酚氧化酶（PPO）以及总酚含量（TPC）。