Boron or manganese, that is the question

[Tomas]

This Brahea was growing happily since quite a few years, and then suddenly...

[Patrick]

Just guessing, but that might be some damage that happened in the winter, like bugs got into the center and had snacks all winter. You only see the damage now that the palm is growing out of it. It doesn't look frizzy and stunted like a boron deficiency...

 

I only bring this possibility up as I had earwigs overwinter in my Jubaeopsis several years back and growth looked like this. Oh, the humanity!

[Merlyn]

I'd also guess cold damage and fungus.  Squirt a little hydrogen peroxide on it and see if it fizzes up.  If you see a lot of bubbles then it's likely fungal damage brought about by cold and/or wet cold.

[Phoenikakias]

I never feed my Brahea armata, generally all Brahea do not need rich soils. Nevertheless I have never had deficiency issues in any Brahea, much more in armata. Does your plant get regularly irrigated? I had recently two of my timer-em valves malfunctioning in a very tricky, sneaky, dangerous manner. The em valves were opening according to time schedule and manually too, but as it turned out not in their full capacity, meaning that many plants in my garden received only little water through drip system or not at all. Very, very, very tricky malfunction, because whenever I tested valves manually they seemed opening nornally, as I could hear water running through.

Edited August 5, 2023 by Phoenikakias