Taro leaf blight, caused by a severely destructive oomycete fungus Phytophthora colocasiae, is responsible for threatening yield loss worldwide. The pathogen has the ability to germinate and spread rapidly to other plants during favorable conditions resulting in acute decline and even death, causing 100% crop loss. Farmers usually rely on highly toxic systemic fungicides to control the disease, which is effective, but residual effects and resistance of these agrochemicals is still a concern. Recently as returning to nature people tend to use chemical-free products, especially edible stuff produced in organic agriculture. Therefore, the use of bio-pesticides and phytochemicals is gaining special attention by scientists as they are ecofriendly non-hazardous, sustainable, and potent alternatives to control many virulent plant pathogens The present research was conducted to assess the antifungal potential of cinnamon essential oils against P. colocasiae. The essential oils from cinnamon bark were extracted using microwave-assisted hydrodistillation equipment, and then their chemical constituents were evaluated using ATR FTIR spectroscopy. The antifungal potential of essential oil was assessed against mycelium, sporangia, zoospore, leaf necrosis, and corms lesions under laboratory conditions at, 0.156, 0.312, 0.625, 1.25, 2.5, 5.0 mg/mL concentrations. Hymexazol was used as positive control and no essential oil as negative control, while each treatment have three replications and experiment repeated twice. The main component of oil was identified as cinnamaldehyde. The pathogen isolated from infected taro leaves was identified as P.colocasiae and then was used as a test fungus in the current study. Repeated experiments show maximum inhibition percentage of mycelial growth, zoospore germination, and sporulation of the fungus were observed at 0.625 mg/mL, whereas leaf necrosis was 100% inhibited at 1.25 mg/mL concentration. This research can be a reference for easy, cost-effective and environment-friendly management and control of taro leaf blight with phytochemicals and plant essential oil derivatives.

中文翻译：

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肉桂精油对引起芋叶枯萎病的 Phytophthora colocasiae 的抗真菌潜力

芋头叶枯病是由破坏性严重的卵菌真菌 Phytophthora colocasiae 引起的，是威胁全球产量损失的原因。病原体有能力在有利条件下发芽并迅速传播到其他植物，导致急剧下降甚至死亡，造成 100% 的作物损失。农民通常依靠剧毒的内吸性杀菌剂来控制病害，这是有效的，但这些农用化学品的残留效应和抗药性仍然令人担忧。最近回归自然，人们倾向于使用不含化学物质的产品，尤其是有机农业生产的可食用产品。因此，生物农药和植物化学物质的使用受到科学家们的特别关注，因为它们对生态无害、可持续、以及控制许多有毒植物病原体的有效替代品 本研究旨在评估肉桂精油对 P. colocasiae 的抗真菌潜力。使用微波辅助水蒸馏设备提取肉桂皮精油，然后使用 ATR FTIR 光谱评估其化学成分。在实验室条件下，在 0.156、0.312、0.625、1.25、2.5、5.0 mg/mL 浓度下评估了精油对菌丝体、孢子囊、游动孢子、叶坏死和球茎病变的抗真菌潜力。以Hymexazol为阳性对照，无精油为阴性对照，每个处理3次重复，实验重复2次。油的主要成分经鉴定为肉桂醛。从受感染的芋头叶中分离出的病原体被鉴定为 P.colocasiae，然后用作当前研究中的测试真菌。重复实验表明，在 0.625 mg/mL 时观察到对菌丝体生长、游动孢子萌发和孢子形成的最大抑制百分比，而在 1.25 mg/mL 浓度下，叶片坏死被 100% 抑制。该研究可为利用植物化学物质和植物精油衍生物简单、经济、环保地管理和控制芋头叶枯病提供参考。