Q. I had gone thru your blogs and thanks for I got idea how to connect with you. I am from the Philippines. I had a small coconut plantation but had some problems I had observed. (Please see attached photos).
A. This looks like basal stem rot disease….Ganoderma…It is usually associated with poor drainage during the rainy season. Water accumulates around the trunks and the soil does not drain well. This standing water causes the palm to weaken and invasion by this disease pathogen which is either in the soil waiting for weakened trees or brought in with the seedlings. I attached a paper that discusses this problem and some corrective measures but the best is preventitive, making sure you have adequate drainage during heavy rains and soil that drains well.
We see similar problems with fruit trees in temperate regions and it is called collar rot. Similar symptoms but different disease organisms.