On Aug 10, I received 3 U. humboldtii plants growing together in a pot of live LFS. I separated them into their own pots - 2 into 100% live LFS and the other in a peat, live LFS, sand, aps mix. Since the repotting, all 3 plants have grown well - put up new leaves & 2 of the 3 have also put up aerial stolons. All 3 are growing in my basement with temps in the middle 60's (~18.9*C) at night and lower 70's (~22.2*C) during the day (*F).
3 days ago I notice that the largest of the 3 plants (in live LFS) developed a reduction in diameter on the stalk of it's newest developing leaf. Today, this developing leaf wilted to the side from this smaller section of stalk. In addition, the leaf that formed 2 weeks ago (largest one on the plant) has darkened significantly and is severely wilted. This pot is sitting in a tray with 1/8 - 1/4" of water & the leaves are ~2" (~5 cm) below 2 T-8 fluorescent lamps.
There are no other visible changes. Other utrics nearby are still growing well (so far) - including the 2 other U. humboldtii from the original pot.
This has the appearance of a fungal attack. Have others experienced this? What are the recommended approaches to resolve this? Is there any hope or should I remove the plant to try & keep the pathogen from spreading? All input is welcome.