Palms of all ages can be damaged, even in the nursery, but vascular wilt rarely becomes important until the palms are at least 10 yrs old. In palms less than six yrs old, the first symptom is the appearance of a single bright yellow leaf in the upper part of the crown. Other leaves in the vicinity of this leaf then become affected, resulting in desiccation and leaf death. Apparent recovery may occur, but affected palms usually die. Mature palms are affected to varying degrees and infection may be chronic rather than acute. Usually, the first obvious sign of the disease is the presence of a few old desiccated leaves. Symptoms may be more noticeable on one particular side of the canopy. Affected leaves normally fracture near their base and hang down. The symptoms spread through the older leaves resulting in a 'skirt' of dead leaves around the trunk. In some cases the palm dies within 12 months of the first dead leaf being visible. A section through the trunk shows marked browning of the vascular tissue, the vessels blocked by gums and other debris preventing the passage of water and explaining the desiccation of the leaves. Vascular discolouring is evident in both cross and longitudinal sections of the rachis/petiole
Cause : Caused by the pathogen Fusarium oxysporum f.sp elaeidis. Spread of this pathogen into new areas depends on the movement of infected soil or palm material, including seeds. The pathogen enters the palm roots through damaged or necrotic tissue. Warm, wet conditions and possibly Potassium (K) deficiency encourage the development and spread of the disease
Control: a) do not plant on sites where the disease has been reported; b) purchase resistant planting material. Do not buy seeds produced in areas where the disease is present unless accompanied of a recognized phytosanitary certificate; c) ensure that the seedlings are healthy and that field nutrition is optimized. Adopt hygienic planting methods; d) clean pruning/felling tools that have been used on a diseased palm with undiluted alcohol or bleach diluted 1:1 with water before they are used on another palm. Progress of the disease cannot be arrested once the palm is infected. Felling and removal of the palm is only beneficial if it prevents an infestation of rhinoceros beetle or other pests. There is some evidence that good agronomic practice retards disease spread and, certainly, maintenance of a high potassium status is beneficial. Replanting on land where palms have died from 'vascular wilt', without some form of crop rotation, is wasteful. In regions where vascular wilt disease is present, resistant varieties of palms should be used for all new plantings
Cause : Caused by the pathogen Fusarium oxysporum f.sp elaeidis. Spread of this pathogen into new areas depends on the movement of infected soil or palm material, including seeds. The pathogen enters the palm roots through damaged or necrotic tissue. Warm, wet conditions and possibly Potassium (K) deficiency encourage the development and spread of the disease
Control: a) do not plant on sites where the disease has been reported; b) purchase resistant planting material. Do not buy seeds produced in areas where the disease is present unless accompanied of a recognized phytosanitary certificate; c) ensure that the seedlings are healthy and that field nutrition is optimized. Adopt hygienic planting methods; d) clean pruning/felling tools that have been used on a diseased palm with undiluted alcohol or bleach diluted 1:1 with water before they are used on another palm. Progress of the disease cannot be arrested once the palm is infected. Felling and removal of the palm is only beneficial if it prevents an infestation of rhinoceros beetle or other pests. There is some evidence that good agronomic practice retards disease spread and, certainly, maintenance of a high potassium status is beneficial. Replanting on land where palms have died from 'vascular wilt', without some form of crop rotation, is wasteful. In regions where vascular wilt disease is present, resistant varieties of palms should be used for all new plantings