Inhibitory mechanism of Citrus sinensis L. osbeck peel extract against the growth of Sclerotium rolfsii Sacc. pathogen causing stem rot disease in peanut plants

Safitri, J., Abadi, A. L., Muhibuddin, A. & Sulistyowati, L. (2024). Inhibitory mechanism of Citrus sinensis L. os-beck peel extract against the growth of Sclerotium rolfsii Sacc. pathogen causing stem rot disease in peanut plants. Bulg. J. Agric. Sci., 30(1), 57–66.Sweet orange is a tropical fruit that is widely cultivated in Indonesia. Oranges are one of the most popular types of fruit. Besides being consumed directly, several types of citrus fruit can be processed into beverages and other processed foods. Sweet citrus fruits are usually eaten whole or processed into drinks after peeling the outer skin (flavedo). This peeling process causes a lot of orange peel waste. Orange peel waste is one of the wastes that can be processed to produce new products that have a high value. Orange peel contains essential oils that can be used as a vegetable fungicide to control plant diseases. One of the most common pathogens is Sclerotium rolfsii. These pathogens are soil pathogens that can survive in the soil for a long time. Currently, synthetic pesticides are the main control of the fungus S. rolfsii. The use of synthetic fungicides can cause resistance and environmental pollution. For this reason, alternative control of S. Rolfsii is needed. This study aims to (i) determine the content of compounds in Citrus sinensis peel extract with GC-MS (ii) to determine the inhibition on the growth of S. Rolfsii (iii) to determine the antifungal mechanism of Citrus sinensis peel extract. The results showed that Citrus sinensis peel extract can be antifungal in suppressing the growth of S. Rolfsii and possibly as a plant-based fungicide. Citrus sinensis peel extract is fungicidal which causes the death of the fungus S. Rolfsii in the treatment of 4.5% and 5% concentrations of phenol, flavonoid, and terpenoid compounds contained in Citrus sinensis peel extract can play a role in antifungal activity against S. Rolfsii by affecting the morphology of hyphae, causing cell walls, and there is no difference in hyphae.