Tasmanian tree fern needs your help- pic attached
My Dicksonia is having some trouble, I'm thinking it is not too late to correct it. I just have no idea what it is.
The pic is not that clear- what is happening is much of the foliage has dried up, a brand new fiddlehead is showings signs of leaflets drying out (still curled tight), and as you can hopefully see in the pic, some leaflets have an orange mid rib. There is a very noticeable yellowing within the leaflets- while the tips are still green. That is where they haven't dried out.
The yellowing reminds me of both a plant lacking enough light and a plant with initial herbicide exposure.
No visible pests- however 2 full months ago I did spray the fern down with a mild soap solution for mealy bugs. I then cut off all but the youngest 5-6 fronds, as the bugs were in the older foliage anyways.
It is indoors in a cool room with decent lighting. Humidity is not ideal but the best I can do.
Anything sounds familiar? Thanks for any help. Would hate to lose it!