Evaluation of Endophytic Microorganisms (Trichoderma hazianum and Bacillus subtilus) as Biofungicides against Bayoud Disease (Fusarium oxysporum f. sp. albedinis) on Date Palm (Phoenix dactylifera L.)

Abstract

Backgraound: Date palm disease named Bayoud, is the major constraint caused by the soil fungus Fusarium oxysporum f. sp. albedinis (Foa) in Algeria. This work has the objective to in vivo biocontrol on bayoud disease incidence on three date palm varieties (Deglet-Nour, Feggous and H-mira), using two antagonistic microorganisms, one fungus (Trichoderma harzianum) and one bacterium (Bacillus subtilus). Methods: Foa strains obtained from isolation of the spines carrying the typical symptoms of Bayoud disease. Two strains used T. harzianum and B. subtilus, are isolated from rhizosphere soils of the date palm. Using the greenhouse screening test, the in vivo biocontrol test is carried out on 3-4 month-old date palm seedlings at the rate of 5 ml of inoculum suspension. Result: A significant (P less than 0.01), difference of date palm seedlings reactions against Foa isolate and antagonistic microorganisms was observed. All three date palm varieties present a high susceptibility against Foa until the total mortality of date palm seedlings. The biocontrol test showed that two antagonists showed different reaction, with the complete resistance of three varieties treated by T. harzianum, while, the antagonist B. subtilus protect just two varieties (Deglet-Nour and H-mira) and can’t protect Feggous variety when showed the susceptibility reaction by presentation of typical symptoms of bayoud disease. We can apply of these antagonistic microorganisms to protect our groves contaminated by Bayoud disease and contain just susceptible commercial cultivars of date palm.