Leaf burn on pinangas

[cobra2326]

MattyB's post inspired me to post some similar problems with strange leaf spots on a few of my pinangas.  

These plants have never seen temps under 60F, and are in nearly full shade.  Current temps are 92-95F day and 70F+ night.  Humidity is about 50% in the middle of the day, gradually increasing to about 90% at night.  They get a bit of direct sun around 10AM.  Funny thing is, on both problem specimens, I have another plant right next to it that is absolutely perfect.  They're still seedlings and I'm using osmocote 18-6-8 granules.  

In the pic of the spear, you can see how the leaves are burned before they even open, which I kind of assumed would eliminate burning from too much light, but who knows.  What gives?  Possibly fertilizer burn?  

Pinanga Caesia

[cobra2326]

Pinanga insignis

[cobra2326]

Spear of P. insignis

[MattyB]

Hmmmm, the P. caesia dosn't look good at all.  I don't like the looks of that.  They usually die when they start looking like that.  On the good note, the P. insignis just looks like minor cold spotting.  But you said that they haven't been exposed to cold so it's probably a leaf fungus.  Spray with fungicide and drench soil with fungicide.

[cobra2326]

Alright, I'll hit them with a fungicide.  You can see it in the pic, but the older P. caesia leaf looks like the photo of the leaf of the P. insignis.  Maybe too much water on the leaves is causing this?

[MattyB]

I've saved several palms from fungus and root rot by gently barerooting in a tub of water and repotting in a fresh, light mix.  You should at least try and pull them out of the pots and take a look at the roots.

[cobra2326]

So you think that root rot may be the culprit?  I do water these things a LOT.

[Dypsisdean]

I have found that Pinanga caesia may be the most "burnable" palm that I have ever grown.

As an aside, I have found Burretiokentias also very susceptible to acclimation burning.

[palmislandRandy]

Looks like burn to me! Every Pinanga frond of mine that ventures out into the sun is toast.    Randy

[cobra2326]

Has anyone witnessed the spears burning before even opening?  That is definitely what happened here, I wasn't aware that was possible?

Dean: I'm glad you made that remark.  Eventually, I want to try this palm indoors.  Humidity generally is about 40-50% year round in my house, and it should make quite a decorative piece!

[MattyB]

Hmmmmm, if you use your imagination and fold the leaf back up into a spear then all the burn occured on the spear on one side.  Am I seeing/imagining that right?  Usually burn occurs on the uppermost or most horizontal leaflets but if it occured while still a spear then you'd get that pattern.