VOLUME ISSUE () 1 D-304 [1-5] RESEARCH ARTICLE Agricultural Science Digest, Volume Issue : () Biocontrol of Bayoud Disease (Fusarium oxysporum F. Sp. Albedinis) on Deglet-nour Variety of Date Palm ( Phoenix dactylifera L.) in South Western Oases of Algeria Hakima Belaidi 1 , Fawzia Toumi-Benali 1 , Ibrahim Elkhalil Benzohra 2 ABSTRACT Background: This work has the objective to biocontrol the bayoud disease of date palm caused by the fungus Fusarium oxysporum f. sp. albedinis (Foa), is the major disease in Algerian palm groves of south western region. This in vivo biocontrol was done on date palm variety Deglet-Nour, using two antagonistic fungi species, Trichoderma harzianum and Aspergillus flavus. Methods: Twenty Foa isolates obtained from isolation of the spines carrying the typical symptoms of Bayoud disease were used. Two strains T. harzianum and A. flavus, were isolated from rhizosphere soils of the date palm trees. Using the greenhouse screening test, which was carried out on 3-4 month-old date palm seedlings at the rate of 5 ml of inoculum suspension. Result: A statistical analysis showed a significant (P<0.05), difference of Deglet-Nour seedlings reactions against Foa isolates and antagonistic fungi were observed. All date palm trees present susceptibility against Foa until the total mortality of seedlings. The biocontrol test showed that two antagonists showed different reaction, with the complete resistance for seedlings treated by T. harzianum with the mortality rate (rm%) reduced at 100%, while, the second antagonist A. flavus reduced the rm% at 25%. We can apply of these antagonistic fungi to protect our groves contaminated by Bayoud disease and also contain this susceptible commercial variety. Key words: Antagonist, Aspergillus flavusflavus, Bayoud diseasedisease, Biocontrol, Date palm, Degle-nournour, Trichoderma harzianum. INTRODUCTION The date palm (Phoenix dactylifera L.) is considered a symbol of life in the desert, while it tolerates high temperatures, drought and salinity more than other crop plant species. It is one of the oldest trees from which man has derived benefit and it has been cultivated since ancient times (Zohary and Hopf, 2000). It the only indigenous wild desert plant definitely domesticated in its native harsh environments appears to be the date palm (Zohary and Hopf, 2000 ; Vinita and Punia, 2016). Among the most cultivated and important varieties in Algeria, Deglet Nour, considered as the golden fruit of the oases, means: Deglet: light; Nour: light, is the best variety in the world (Munier, 1974). The Algerian palm groves represent 45% of Deglet Nour variety cultivation (Bouguedoura et al ., 2008). The annual production of Deglet-Nour variety of dates is 5670000 quintals (Statistica, 2020), which represents 51,8% of total Algerian date palm production (Fao, 2020). The date palm sector has many problems like sand dunes, salinity, secheresse and seriously damaged by Bayoud disease (Touzi, 2007; Benzohra et al., 2015), which destroyed a half date palm trees of Algerian palm groves in the south-west region (Bouguedoura et al., 2008). Bayoud disease caused by the soil fungus Fusarium oxysporum f. sp. albedinis (Foa), is considered as the most destructive fungal disease in south west of Algerian palm groves (Djerbi, 2003). It’s originated from Morocco and its progression continues to advance from the west and central of Algerian palm groves (Benzohra et al., 2015; 2017). The proposal used of prophylactic measures against this disease doesn’t seem able to stop progressive spread of this disease (Benzohra et al., 2017). Other method was used, a genetic control by resistant varieties is therefore another promising way to reduce this constraint, but unfortunately all resistant cultivars haven’t high food quality in date fruits (Sedra, 2005a,b). It is necessary to protect this variety (Deglet-Nour), against this constraint with an effective method that does 1 Laboratoire Ecodeveloppement des Espaces, Department of Environmental Sciences, Djillali Liabes University of Sidi Bel Ab- bes, Algeria. 2 Department of Phoeniciculture, Experimental Station for Biophysical Environment Bechar (Taghit) - Centre for Scientific and Technical Research on Arid Regions (CRSTRA), Campus Universitaire B.P. 1682 RP, Biskra, Algeria. Corresponding Author: Hakima Belaidi, Laboratoire Eco developpement des Espaces, Department of Environmental Sciences, Djillali Liabes University of Sidi Bel Abbes, Algeria. Email: hakimabelaidi8@gmail.com How to cite this article: Belaidi, H., Toumi-Benali, F., and Benzohra, I.E. (2021). Biocontrol of Bayoud Disease (Fusarium oxysporum F. Sp. Albedinis) on Deglet-nour Variety of Date Palm (Phoenix dactylifera L.) in South Western Oases of Algeria. Agricultural Science Digest. DOI: 10.18805/ag.D-304. Submitted: 15-08-2020 Accepted: 30-10-2020 Online: 01-03-2021