Thanks for your reply! I am thinking of going with the former camp and keeping it and trying to get it healthy. The disease appeared after really heavy rains and I feel like it was drowning in its pot. The only thing I'm afraid of is the disease spreading to my non fig trees I have on the same balcony (pakistani mulberry, starfruit, guava). Do you think this is a concern?

Iron Tone works for me.

To check for fig bud mites you need good magnification, they are basically microscopic. I use this 40x handheld microscope. https://www.amazon.com/Active-Eye-AEM40-Microscope-Magnification/dp/B003UL935O

The mites will be on the underside of the newest leaves, to see them well you may need to pick the leaf and put it on a table to get it steady and focus the microscope to watch for movement (they blend well with the leaf trichomes). People often assume fig bud mites are similar to spider mites, but they are much smaller and harder to treat. As a result of them being hard to detect and eradicate they are fairly common in collections and nurseries.

If there are fig bud mites and the fig tree does have FMV they may transfer it to your mulberry tree, there is also a chance other fig viruses like FLMV, FMMV etc. could be transferred by other specific vectors which may or may not be known such as aphids or mealybug. Fig badnavirus and possibly others can be transferred to the mulberry through pruning tools as well.

In addition to giving the plant optimal growing conditions, heavy pruning will help to invigorate it.

The virus is specific to figs.

Won't spread to other genera.

Hi Jean, I double checked my answer and confirmed FMV is shown to be graft transmissible to Morus indica. While the fig bud mite has not yet been shown to transmit the virus to mulberry, it is able to transmit to other indicator plant species. Fig Badnavirus-1 was found in 33% of mulberry trees tested in Iran.