I've had my Ming Aralia for about 2.5 years now and it would occasionally drop leaves and branches. As of this spring (approx 1.5 months ago) the leaf and branch dropping accelerated to the point that even new growth is quickly yellowing and dying.
I've had fungus gnat issues in the past, but I rarely see them near the plant now.
I water it occasionally, but not excessively. It gets moderate sun throughout the day, and the weather has been humid but not too warm or cool.
Any suggestions as to what I should do? Really old growth is still present, but as you can see in the pic below, nearly half the branches on one side have fallen off.