Résumé
Fusarium wilt of date palm (Phoenix dactylifera L.), caused by Fusarium oxysporum f. sp. albedinis, continues to threaten oases across the Maghreb. However, the disease has failed to establish in Southeastern Algeria, despite the ongoing movement of potentially contaminated plant material. This study investigated whether soil chemical properties contribute to this apparent epidemiological boundary. A total of 48 soil samples were collected from healthy and diseased date palm groves across infected (Adrar, Ghardaïa) and uninfected (Biskra) regions. Soils were analyzed for pH, electrical conductivity (EC), organic matter, calcium carbonate (CaCO 3), soluble cations (Ca 2+, Mg 2+, Na +, K +), and available phosphorus (PO 4 3-). While no consistent differences were observed between healthy and diseased trees within infected areas, five parameters-EC, Ca 2+, PO 4 3-, Mg 2+, and CaCO 3 differentiated uninfected from infected regions. Higher levels of EC, Ca 2+, and CaCO 3 in uninfected soils suggest a suppressive effect on the pathogen or enhanced host resistance. These findings align with previous studies showing that elevated salinity and calcium can limit Fusarium development by altering cell wall integrity, enzyme activity, and spore production. Phosphorus and magnesium may further modulate disease expression through effects on plant immunity and pathogen metabolism. Our results support the hypothesis that F. oxysporum f. sp. albedinis is constrained by edaphic factors in Southeastern Algeria. This study highlights the importance of soil chemistry in shaping pathogen distributions and suggests that nutrient-based management may help suppress Fusarium wilt in date palm agroecosystems.
Vascular fusarium wilt of date palms (Phoenix dactylifera L.) is a disease caused by Fusarium oxysporum f. sp. albedinis (Killian and Maire). This telluric fungus attacks almost all varieties. This disease continues to decimate 4.5%-12% of the world's palm groves annually, causing significant genetic erosion and major production losses (Djerbi 1982, 1988; Sedra 2011). While this disease is a scourge for a large part of North Africa's palm groves, it also represents a permanent epidemiological threat, in human, social, and economic terms, to palm-growing areas that are free of it. It is therefore essential to identify the factors that promote or hinder the spread of the disease. Ghardaïa has been at the forefront of the disease spread to the eastern regions of the country since it was first reported there in 1965 (Dubost and Kada 1975; Djerbi 1982).
The slow progression of the disease over the past 50 years suggests that edaphic factors may limit its spread. The study aims to understand why the disease has not spread to palm groves in southeastern Algeria, despite the absence of strict control of plant material. Among the various environmental parameters that interact with the host plant and the causative