Hi, I'm new here but I have an urgent question. I have what I believe to be a Ginseng ficus bonsai. I received it as a gift a year ago. It seemed to be doing fine for this time. It regularly shed leaves and grew more. Was not wilting and i've never had a pest problem. Recently however, I seem to have been neglectful and i've noticed the trunk of the bonsai has wrinkled and feels quite soft. More than half of it's leaves have fallen off (around 20 or so) in the past week. Before this it would only lose 1 or 2 every couple months. I suspect it might be rotting from over watering or under watering?
I water it usually with rainwater or filtered on very rare occasions once or twice a week. In the pictures I include, you can see the leaves that dropped off are a tad yellow. The brown is because they are a day or two fallen. Also, one of the roots coming from the large trunks was hollow and dry so i cut that away before I took the photos. The only residue I could find is the white stuff on the one trunks base. I also cut a little piece of the bark to see if it was still green underneath and thankfully it is. I hope that means I can save it somehow? If you have any information on how to save my little bonsai or how it got this way I would be much obliged!
I forgot to mention, it is inside most of the time. In the warmer months I would take it outside for 5-6 hours. It sits on my window sill in my room but it is close to my heater. It's an old cast iron heater so no vents. The only draft is my window air conditioner ( another window) that blows air in sometimes. My house does not have many windows facing enough light so it really doesn't get the best. It stays around 67-70 F in my house. It is 50-30 F outside and starting to snow. I take it outside during the day if it is above 45 F. Also, I live in the US, NE Ohio to be exact.
I realize that was a lot but anyone who got this far and has information, I'd be so grateful for your help! Thank you.