A few months ago,when my bicalc outgrew the small terrarium, I set it up in one that was larger, but had less ventilation. I made the mistake of setting the pot in the water, and proceeded to neglect my poor nep for several months. (I also made the mistake of setting the terrarium up in a room I rarely visit.) aside from making sure it had water, I wasn't paying attention as I should have.
This is the result.
image by Jerabudragoness, on Flickr
About half of the lower/older leaves look like this. Newer larger leaves are relatively untouched.
I'm assuming fungal, and have bought some Concentrated propiconazole. I have not yet started treatment.
When I first realized my mistake, I took the following actions:
I repotted it in a net pot with clean media, a blend of perlite, dried spag, and cypress mulch. I do not have live spag, or I would have used that. The old media was similar, but not in a net pot, and did smell sulfurous upon removal.
I also moved it into a smaller, but better ventilated terrarium, sitting on egg crate raised above the water. There is an ultrasonic fogger in there keeping things humid, but it is allowed to ventilate as well.
While repotting. I noticed the roots and stem look fine and healthy, with no signs of rot or disease. Nothing mushy, and after washing the old media from the roots, no smell.
My quiestions are
1 does this look fungal?
2 would it be advisable to prune off the worst of the leaves? Leaving the plant with approximately half of its leaves?
3 do I dilute the propiconazole according to package directions, or is there a recommended dilution? Package directions say 2-4 ounces per 100 gallons, so literally a few drops for one gallon, or do I go stronger?