So here it is. I bought a bonsai ficus at Wal Mart several months ago, not to start bonsai-ing but because it was on sale for $4.00 and it was going to die at the store otherwise. It had two trunk coming out of the soil that merged together at the top and the growth at the top of the "triangle trunks." (The tree looked like a triangle, the base of the triangle being the soil, if that helps) The branches with growth are not enough to begin training yet so I am letting it grow a bit.

Well, one of the trunks began to shrivel up, it was dying most likely from root rot because the soil was covered with glued-together rocks. I ended up cutting off the dying trunk until I reached non-decayed wood. So there is a big scar there.

But then the scar began to cave in as if it were being "eaten". Inside the scar there was white stuff covering the surface. I think it was a mildew or something to that effect. I thought that when a part of a tree is cut off, the part would heal without caving in?

Please help. If you need photos let me know.

Thanks.