I can’t find photos with similar problem in the internet. Therefore, I don’t know how to treat this. Please help me, the tree looks worse each day.
Unfortunately, this is pretty hard to treat. In my experience you can combat this by spraying the plant with neem oil. Remove the leaves with the fuss and dispose of them in a plastic bag so they do not contaminate any other plants. Spray the tree once a week with the neem oil. Any leaves that are dead or yellowing prune off the tree. Then to strengthen the tree fertilize it to give it a fighting chance.