شناسایی ترکیبات فیتوشیمیایی اسانس‌های مرزه خوزستانی و علف لیمو و بررسی تاثیر نانوامولسیون های آنها در مهار جوانه‌زنی هاگ قارچ Podosphaera fusca در شرایط آزمایشگاه

Podosphaera fusca, the causal agent of powdery mildew disease, is one of the most important pathogens that limit the yield of cucumbers, which has a high rate of resistance to fungicides. Therefore, it is necessary to find and effective and low-risk natural alternative compounds such as essential oils of medicinal plants. Plant essential oils face problems and limitations in their application due to very low solubility in water, volatile nature, and poor chemical stability, therefore, encapsulation of essential oils on a nanometer scale and combining them with polymer coatings has been suggested, In this investigation, the aerial parts of khuzetani savory (Satureja khuzistanica) and lemon grass (Cymbopogon citratus) were collected in the flowering stage and their essential oils were prepared by hydro distillation. The chemical compounds of the essential oil were identified by gas chromatography coupled with mass spectrometry (GC-MS). Nanoemulsions of essential oils were prepared by adding the optimal concentration of surfactant and lecithin in water with the help of a homogenizer, and their effect on preventing the germination of conidia of Podosphaera fusca was studied under laboratory conditions in a desiccator. The results of GC-MS analysis showed that carvacrol with 87% is the predominant composition of Khuzestani savory essential oil and the main components of lemongrass essential oil include citral 42/6 , citronellol 20/3 and geraniol 16/4. The results of the effect of foliar spraying with concentrations of 2 and 3 per 1000 of nanoemulsions in inhibiting the germination of conidia on the infected leaves in the desiccator showed that the nanoemulsion of Khuzestani savory and lemon grass inhibite 83.67 and 74% of the conidia germination, respectively whereas the fungicides Topas and Kresoxim methyl (in the recommended dose of 0.5 and 0.4 per 1000, respectively) inhibited 75.4 and 65.67% of conidia germination, respectively. finally, it is suggested to study the nanoemulsion of both essential oils in controlling cucumber powdery mildew disease in the greenhouse.