Q.Sago Palm (Cycad)
I have a huge (really huge) sago palm planted outside my home. It is approximately 17 years old. It has been healthy with no effort on my part. 4 or 5 years ago we had a freeze which literally killed it – I thought. All the fronds turned yellow, brown and died. I cut all fronds off down to the stump. It grew back twice as large! In January of this year we had 2 nights of freezing weather. I had it covered as best I could, but a small part of it did freeze. It seemed to be doing okay but about 2 or 3 months ago I noticed something that looked like salt covering the ground on the East side of it. I truly thought nothing about it (I don’t know why I was not concerned) and later saw the salt was gone. Now the fronds are turning yellow and it looks like it is dying. I have been cutting the yellow fronds off and yesterday raked and swept as much debris out from under the plant as I could – and I saw the dirt under the plant was very dark and had the “white salt” in it. What do I do to save it?
It sounds like a Scale infestation.
This article will help you.
https://www.gardeningknowhow.com/ornamental/trees/sago-palm/white-spots-on-sago.htm