Unique Brown Blotches on Coconut Palm Fronds?

[Hempress]

Hello!  I have an issue with my coconut palm trees as they are developing a dead, lace-like rash (brown dead spots/blotches - not bugs) in a consistent pattern on the fronds. It started when the nights began getting colder in Silver Springs, Florida (Zone 9b) last week 10/20/22 (43 degrees). The only reason why I think it MIGHT be chill damage is because it began at this time. I don’t think it is a fungus because the spots are not watery, blurry or bleed to yellow/dead, but are more sharp, embedded and consistent in pattern. (see pics?). It doesn’t really look like a Manganese or Potassium deficiency and if they were sunburned wouldn't the end/tips and certain areas be more dead than others?  At this point, I’m not sure of anything!?  Nothing resembles this condition on Google :/? Does anyone know what this could be? Thanks very much!

[SeanK]

Scale. Maybe horticultural oil, maybe insecticide.

[aztropic]

You guessed correctly. Absolutely cold damage! 

 

aztropic

Mesa,Arizona

[Merlyn]

Yeah, I would guess cold damage too.  Individual plant cells (or groups) got cold enough to die, and you just caught it at the right time to see the edges be fairly distinct.  Usually the dimples aren't quite so obviously well-defined.

[Hempress]

Thanks so much everyone - last night I put string lights in the pots to warm the roots and this morning the condition did not "spread" ... your input was most appreciated!

[Johnny Palmseed]

Silver Springs is not an area that a coconut will survive without extensive protection. You have listed it as zone 9b but that is incorrect. It is 9a at best, unless you are near a lake or have canopy. As you can see, it’s only October and you have already sustained cold damage with temps in the 40s. I would not recommend planting it in the ground. You could keep it potted for years but it will become heavy and unwieldy.