my four Ficus trees which has been planted 17 years ago , and are next to each other are shedding their leaves since ten days ago
in a very speedy fashion unlike other Ficus around us . my four Ficus trees are loosing their leaves in a way that inside of the trees getting hollow. the other ficus trees around us are healthy. The leaves that are falling down have either yellow spots on them ,or they are green , or completely yellow . I have been looking for solutions in nurseries around. Could you please help me what to do ?
It would seem that the tree has sustained some sort of fungal or bacterial infection. You can attempt to correct this with wettable sulfur, and a little dolomitic lime to keep the pH of the soil stable. If your tree is starting to become hollow, then it is likely that the tree had some damage that become infected and has been like that for awhile, even if it didn't have symptoms. Treat with sulfur, and you can at least kill off what is in the soil. The tree may or may not be able to recover when this is done, being so far along in the process. You can try and take a cutting to preserve the tree. This will grow into a full sized tree after some time.
Here is an article on taking cuttings: https://www.gardeningknowhow.com/ornamental/trees/tgen/how-to-root-cuttings-from-various-shrubs-bushes-and-trees.htm
Here is a collection of articles on the ficus tree: https://www.gardeningknowhow.com/houseplants/ficus/