Study of the Influence of Previous Vegetation and the Induction of Immunization of Oil Palm (Elaeis guineensis) against Fusarium Wilt

Study Design: One of the major challenges in the control of oil palm Fusarium wilt at prenursery stage for seedlings protection by pre-inoculation with a saprophytic strain of Fusarium oxysporum lies in the persistence of the defence induced under a high parasitic strain‘s pressure characterizing old oil palm plantations areas at replanting.
Place and Duration of Study: Prenursery area of the National Center for Agronomic Research (CNRA), research station Robert Michaux of Dabou and oil Palm Physiology and Pathology Laboratory, between October 2009 and May 2010.
Methodology: The assessment of the influence of the Fusarium wilt history of an oil palm plantation on the acquisition of protection by the next generation of oil palms was performed on 2-months-old oil palm seedlings, sensitive to Fusarium wilt and growing on three types of soils characterizing the different Fusarium wilt history.
Results: The protection inducing treatment, characterized by the pre-inoculation of the non-pathogenic strain of Fusarium oxysporum (Fot) in the root system before the inoculation of the pathogenic strain F. oxysporum f. sp. elaeidis (Foe), has reduced the number of diseased seedlings at a rate of 24% against 35% when only the pathogenic strain Foe was inoculated in the seedlings, independently of the type of soil. Nevertheless, the expression of Fusarium wilt was delayed for a few weeks, only on the extension soil, and only in the case of pre-inoculation with Fot.
Conclusion: The biological control of oil palm Fusarium wilt at prenursery stage can only be, for the moment and under the conditions specified herein, rationally envisaged in new areas and not in replanting of old oil palms’ areas.