Recently a member had a rain tree that suddenly started turning yellow and dropping leaves. This, as one could guess, caused him some panic.
This is his tree.
I assured him this was a natural occurrence. And showed him my tree.
Mine looks much worse. As you can see.
It is the time of year that passes for winter here in Orlando and the Brazilian rain tree, which is usually a heavy drinker, almost stops using water at this time. I believe it goes dormant (as much as a tropical plant can go dormant) during winter and will defoliate if given too much water. It must be noted; this yellowing and dropping leaves can also happen when nematodes are present. But usually only when the tree was field grown or spends too much time on the ground.
One way to tell the difference is to look for dormant buds at the nodes.
This is a healthy bud and I, for one, am not worried about my tree.
I will give it a dose of iron to green it a bit and ignore it.
Until it is time to protect them from the cold.
Which is another posting.