Antifungal Effect of Ambrosia artemisiifolia L. Extract and Chemical Fungicide Against Spilocaea oleagina Causing Olive Leaf Spot

Olive leaf spot or peacock eye disease caused by Spilocaea oleagina is one of the most common diseases attacking olive trees all over the world. Control of the disease by application of copper fungicides is not always feasible and requires proper management practices. The use of plant extract is considered a safe alternative to the harmful effect of chemical fungicides. In this work, different concentrations (0.5, 1.0, 1.5, 2.0, 2.5, 5.0 and 10% w/v) of Ambrosia artimisiifolia aqueous leaf extract were tested for their efficacy against OLS spore germination. All concentrations proved to have an inhibitory effect on conidial germination under in vitro conditions. The concentrations 2.5 and 5% were the most effective with germination rates of 8.3 and 2.8%, respectively. The results of this work provided new possibilities to control the disease using A. artimisiifolia leaf extract.