Coffee production is negatively affected by coffee leaf rust, a disease caused by the fungus Hemileia vastatrix. As a natural product-based alternative to chemically control the disease, this study evaluated the effect of two chitosan-coated nanoemulsions prepared from Cymbopogon citratus essential oil (EO) and the thymol: pyruvic acid (1:1) natural deep eutectic solvent (NADES) on the in vitro germination of H. vastatrix urediospores and on the in vivo control of the disease in Coffea arabica plants under greenhouse conditions. Both nanoformulations inhibited urediospores in vitro germination but only that prepared with EO did it significantly more than its free form active ingredient (the observed reduction was around 60 %). On the other hand, the in vivo experiment showed that the EO and NADES chitosan-coated nanoemulsions offered similar and significant protection for Coffea arabica plants against leaf rust; the disease severity level was found to be less than 2.6 % after 81 days from the application of the treatments to the plants (comparable to the cooper oxychloride, which is one of the commercial fungicides traditionally used), while the free components did not (9.0–13.3 % of severity level by day 81, such as the control). This is the first report demonstrating that chitosan-coated nanoemulsions, containing NADES or EO, protect coffee plants against H. vastatrix infection and can be two alternatives for sustainable pest management. Furthermore, this study contributes to broadening the prospects for using hydrophobic NADES in the design of biopesticides.

中文翻译：

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壳聚糖包衣的萜烯基天然共熔溶剂和柠檬草精油的纳米乳液，用于控制咖啡叶锈病：基于天然产物的两种替代方案


咖啡叶锈病对咖啡生产产生负面影响，咖啡叶锈病是一种由真菌 Hemileia vastatrix 引起的疾病。作为化学控制疾病的天然产物替代品，本研究评估了由柠檬酸钹精油 （EO） 和百里酚：丙酮酸 （1：1） 天然共熔溶剂 （NADES） 制备的两种壳聚糖包衣纳米乳剂对 H. vastatrix urediospores 体外发芽和阿拉比卡咖啡病害体内控制的影响温室条件下的植物。两种纳米制剂在体外抑制尿道孢子的发芽，但只有用 EO 制备的纳米制剂比其游离形式活性成分明显更多（观察到的减少约为 60%）。另一方面，体内实验表明，EO 和 NADES 壳聚糖包被的纳米乳液为阿拉比卡咖啡植物提供了类似且重要的叶锈病保护;对植物进行处理 81 天后，发现疾病严重程度低于 2.6%（与传统上使用的商业杀菌剂之一 Cooper Oxychloride 相当），而游离成分则没有（到第 81 天达到严重程度的 9.0-13.3%，例如对照）。这是第一份证明含有 NADES 或 EO 的壳聚糖包衣纳米乳剂可以保护咖啡植物免受 H. vastatrix 感染的报告，并且可以成为可持续害虫管理的两种选择。此外，本研究有助于拓宽在生物农药设计中使用疏水性 NADES 的前景。