I got my first nepenthes, a reinwardtiana (highland red) around July 4th:
I filled the pitchers with a few drops of distilled water. The brown spots and the small yellow leaf concerned me so I sent an email to the seller, but never got a reply. I also found a single scale on a fallen leaf, which I disposed of. No other scale were spotted since then.
After a while I noticed that the yellow leaf had gone soft and black.
I cut it off before the black could reach the stem.
This was the beginning; for the next week or two I had to fight of spontaneous appearances of black spots, usually beginning on tips of leaves. Then the pitchers were affected.
The black would appear in a matter of hours. Sometimes appearing at evening when it wasn't there in the morning, sometimes appearing literally overnight in the morning. Shears were always disinfected before and in between pruning affected parts, and always before the black reached too far in. I started cutting at the first sign of blackness.
I suspected fouling of the substrate and took away the live sphagnum I topped the pot with; the lfs looked normal, but I still carefully lifted the plant out of its pot. The mix was standard lfs with a smattering of perlite, and it looked fine with no odor. I tried pulling it away from the roots since the whole thing was a ball of sphagnum, but gave up when I felt resistance. I was afraid I'd damage the roots, which I suspect were filling the pot. Instead I flushed the sphagnum with distilled water and repotted in a bigger container, filling around the root ball with ABG mix (which is orchid bark/tree fiber/milled peat/milled sphagnum/charcoal if I recall correctly) and topped with more fresh sphagnum.
After this there was peace. My reinwardtiana seemed pretty happy, putting out a new pitcher with another on the way.
The dark tips on the older leaves were present from the day it arrived, and I assumed they were places were pitchers dried and died. Unlike the creeping black spots they didn't spread and were not soft so I didn't worry much about them.
But then I found this:
Notice the dark coloring crawling up the vein. I panicked and pruned. It's more pronounced on the underside:
And now I'm afraid I'll have to deal with the constant watch and pruning again. The bottom portion of the stem is black but not soft, like how the tips of the older leaves were. I assumed this was normal for older growth but am not sure anymore. What even is this? What can I do?