Dear Ernest and David,
Yes, the root system is the first place I would look for disease organisms and in West Africa my first thoughts are oil palm wilt caused by Fusarium oxysporum f. sp. elaeidis.
I have pasted info on symptoms from the CABI Crop Protection Compendium plus one image of the a seedling base showing internal discolouration.
"The pathogen can attack oil palm at all ages from seedling to mature palm, and Prendergast suggested that in mature palms the disease can exist in two forms. In the chronic form, the older leaves become desiccated, the rachis breaks near or at some distance from the base and hangs down around the trunk. The disease progresses gradually, with younger leaves becoming successively affected whilst the erect young leaves in the crown are much reduced in size and may become chlorotic; the apex of the trunk may also reduce in diameter. Palms can exist in this condition for several years.
Alternatively, a palm may display the acute form of the disease, in which leaves dry out and die rapidly while retaining their original erect positions on the plant until broken off, usually several feet from the base, by wind action. The disease progresses rapidly and palms die within 2 or 3 months.
Various intermediate stages between the acute and chronic forms may occur. A third category of temporary wilt where palms develop leaf symptoms but later recover. On immature palms, leaves in the middle of the crown become yellow or brown; this first spreads to lower neighbouring leaves but eventually the palm will totally desiccate and die. At the nursery stage, infected palms show progressive shortening of younger leaves and desiccation and death of older leaves. These symptoms are thought to result from a combination of water stress (caused by xylem vessel blockage) and changes to plant gibberellin levels or activity.
Internally this disease is characterized by discoloration and blockage of xylem vessels with tyloses and gums. Vascular discoloration (from healthy cream to infected dark brown) is always observed in palm stems, and in severely infected plants it can spread systemically to the petioles. However, even in highly diseased field palms most roots show no signs of infection."
CABI Crop Protection Compendium
Has oil palm been grown on the site before and if so were there any problems? Oil palm may have been grown 7-8 decades ago and abandoned and now the area has been reused but there is not ‘corporate memory’ of the palms ever being grown there. Once the oil palm wilt fungus chlamydospores are in the soil then they are there forever. Some clones do better at resisting the disease that others.
The Nigerian Institute for Oil Palm Research has experimental stations and sub stations (http://nifor.gov.ng/) log on to the website for further info as one of these may be near to the infected site and it might be easy to contact them.
Seedling base showing internal discolouration.
Please upload some images and also mention your location. Thanks almost 7 years ago.
Ok. My location is Uyo, Akwa Ibom, South-southern Nigeria. I sure would make the images available as soon as possible. Thanks for your interest in this concern.
almost 7 years ago.
Hello, I'm now ready with pictures of the affected plants almost 7 years ago.
Go to the edit option in your question and upload images there. almost 7 years ago.
The pictures are now ready and put on the platform, waiting earnestly for your kind responses. Thank you. almost 7 years ago.