<div>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&lt;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.</div>

<div>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</div>