I am confused by what is causing it. I have both the variegated form and regular of Abtusifolia and only the regular is showing the signs. I can not figure out why this might be happening. The plants are side by side under the same light in the same size pot with the same soil type. The damage/infection/whatever looks a little similar to what my jade plant does when I neglect it too long and it dries out a bit too much. I doubt this but it is possible. The newer leaves are looking really strong and I have been watering a little more than before. I water them with rain water at room temp. The pot are well drained, sitting on loose rocks so they don't stand in any water. Lighting is 2 48 inch t8 6500K bulbs. Very root bound, is only thing I can think of I might need to do to alleviate the problem.
The first thing that came to my mind was salt buildup; do you allow a good water run-through when you irrigate? The other thing is that if plants are root bound enough, they don't absorb water/nutrients like they should, so I would add a vote for repotting, maybe with some root pruning.
Salts may be possible but I use only rain water on them and not the first rain either. I think it is time to repot anyway so I will see if that helps.
No sunlight, just kept under two 48 inch T8 6500 K fluorescent bulbs. I can get a picture of the whole plant in the morning but it looks healthy and strong.
The plant in the middle is the one with the problems. The variegated one hasn't had any issues yet. The leaves that were bruised came from all parts, upper, top, middle and lower. I have not seen any problems since I removed the leaves that looked bad. I plan on re-potting soon into a larger pot although I may need to go smaller than the ones I have. Not sure with all have read that a 6 inch pot isn't going to be too big for best health of the plant.
Looks healthy enough to me. It's always a good idea to repot and examine the old soil and the root structure and condition. Sometimes there are virus or fungus within the plant that will eventually die. There is no remedy for the poor plant but surely you should get rid of the soil or bake it and bleach the pot before using it again.
Wow your plants are absolutely beautiful! Looks like a flower bud on the variegated one. Not what I expected to see from those leaves. Any rootbound plant will not be able to perform at its' best, if there is no more room for roots to grow. As roots circle around in a pot, some can strangle the others. The leaves serviced by those roots can be compromised when that happens, which would look similar to overwatering. If it's really packed in there, moisture may not be penetrating well, so that could cause some leaves to be lost to dehydration. Your plant looks great though, hopefully a repot and more root room is all it needs. If the soil does not harbor excess moisture, no pot is too big.
