The production of cereals in Morocco has experienced fluctuations due to various factors, including cryptogamic diseases. The control of these diseases still relies heavily on chemical products that harm the environment. The objective of this study, was to test an alternative method that improves yield and is environmentally friendly in controlling helminthosporium leaf spot disease caused by Bipolaris sorokiniana, using essential oils extracted from medicinal plants. The effect of two essential oils, Origanum compactum and Thymus satureioides, was tested against helminthosporium leaf spot on four varieties of durum wheat (Triticum durum) and common wheat (Triticum aestivum). These two essential oils were applied to the aerial part at a concentration of 0.31 µl/ml for Origanum compactum essential oil and 1.25 µl/ml for Thymus satureioides essential oil. The different parameters evaluated included the types of infection, the greenness rate on the top two leaves at the flowering stage, grain weight, the number of grains per spike, and the weight of a thousand grains. The results showed that both essential oils significantly reduced disease severity by 48% and increased grain yield by an average of 25% across all varieties used. Thymus satureioides was found to be more effective than Origanum compactum, reducing the infection rate by 52% and improving productivity by 50%. These results indicate that the control of this disease can be achieved without the use of synthetic chemical products.
Keywords: Helminthosporium leaf spot, Wheat, Bipolaris sorokiniana, Alternative control, Essential oils, Origanum compactum, Thymus satureioides