Effect of Olive Mill Wastewater of in the Control of Olive Verticillium Wilt Caused by Verticillium dahlia Kleb

Muhrez, K.A., M.Z. Tawil and B. Barhoum. 2021. Effect of Olive Mill Wastewater of in the Control of Olive Verticillium Wilt Caused by Verticillium dahlia Kleb. Arab Journal of Plant Protection, 39(4): 273-280. https://doi.org/10.22268/AJPP-39.4.273280 This research aimed to evaluate the application of olive mill wastewater in controlling Verticillium dahliae the causal agent of olive wilt disease on olive trees. This study was carried out on 2 years old olive local variety (Khderi) plants planted in pots after it has been artificial inoculated with V. dahliae, and severity was recorded within 90 days. Olive mill wastewater (omww) efficacy was estimated at the end of the experiment. Severity was increased from 8.89% before treatment to 28.89% 60 days after treatment, and decreased to 13.33% 90 days after treatment with omww 450 ml/l. Disease severity increased from 11.11% before treatment to 37.78% 60 days after treatment and decreased to 35.56% 90 days after treatment with omww 300 ml/l. Whereas, disease severity increased from 17.78% before treatment to 40% 90 days after treatment with azoxystrobin compared to the inoculated control where disease severity increased from 13.33% before treatment to 100% 90 days after treatment. Omww 450 ml/l had the highest efficacy of 80% followed by azoxystrobin 70%, and omww 300 ml/l 57.33%. It can be concluded that olive mill wastewater has a potential application as a bio-fungicide for the control of olive verticillium wilt disease. Keywords: Olive mill waste waters, Verticillium dahlia, olive, Fungicide.