Evaluation of Garlic and Thyme Oils Activity Against Powdery Mildew Disease of Caraway (Carum carvi, L.)

Abstract

Egyptian Journal of Horticulture https://ejoh.journals.ekb.eg/ 17 T HIS study aims to evaluate the effectiveness of garlic (Allium sativum) and thyme (Thymus vulgares) essential oils for controlling powdery mildew disease (Erysiphe heraclei fungus) on caraway (Carum carvi L.) plant. Green house and field experiments were set up as splitplot design with7 treatments; garlic and thyme essential oils at 0.5% and 1.0% concentrations (severally), chemical fungicide (Flint 500) at 0.2 and 0.4 g/L. concentrations and control (sprayed with distilled water).The spray application of these treatments were applied at two different stages (before and after appearance of disease symptoms) for three times with one week interval. All treatments significantly reduced the powdery infection compered to control. Under the field conditions, garlic oil showed the highest resistance response of caraway plants against powdery mildew. This was reflected on yield and quality components of caraway crop, whereas the umbel number, fresh weights (g), per plant, weight of 1000 seed (g), seed yield and oil percentage in all treatments were significantly improved compared with control. Whereas the spray application before the symptoms appeared being more effective in this regard. When gas chromatography-mass spectrometry analysis for caraway seed essential oils of the different treatments, a differences were appeared in constituents and their percentages. The main components were carvone and limonene in the all treatments. consequently, it could be concluded that plant essential oils valuable for controlling powdery mildew disease as a safe alternative option to chemical fungicide.