Noueichi, A., S. Chibani, A. Othmani, M. Boukbach, W. Abdelaziz and R. Mouna. 2023. Effect of Eucalyptus globulus Oil on Growth of The Fungal Pathogen Fusarium oxysporum f. sp. albedinis, The Causal Agent of Date Palm Bayoud Disease in the Laboratory. Arab Journal of Plant Protection, 41(3): 281-284. https://doi.org/10.22268/AJPP-41.3.281284 Fusarium disease of date palm caused by Fusarium oxysporum f. sp. albedinis, commonly known as Bayoud disease, is a serious threat to date palm cultivation in North African countries including Algeria. The inhibitory activity of eucalyptus oil (Eucalyptus globulus) was evaluated in the Plant Biology Laboratory at the University of Constantine, Algeria. The results obtained showed significant inhibition of fungal growth which varied between 17 and 60% based on the concentration used. The pathogen inhibitory effect was mainly due to the presence of monoterpene compounds which have a strong inhibiting property against fungi. The results obtained suggest that Eucalyptus essential oil is potentially a safe and effective alternative to chemical fungicides, but field evaluation for its ability to control date palm Bayoud disease is essential before recommending its use in farmers’ fields. Keywords: Date palm, Fusarium oxysporum f.sp. albedinis, essential oil, Eucalyptus globulus