I am sorry for this delayed reply to your gardening question as we are transitioning to a new Q&A system. I hope this reply is not too late to be of help.
I suggest you take a photo of the palm or some samples from it to your County Extension Office for them to look over. The description of the problem does not point to any one cause. If the soil is not well drained and stays too wet this can cause yellowing. However it is also possible that you palm has scale insect attacking it. With a photo or sample in hand your local Extension Office should be able to make an accurate identification or diagnosis.
Thanks for the question. Please stop in again soon!
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