Q. My orange has lots of blossoms, they begin to set the fruit, but when the fruit becomes the size of a pencil eraser, the fruit drops off the tree. What is going on? I watered it, and applied fertilzer.   A. I have two questions that might shed more light: 1. Is this tree planted less than three years ago? and 2.  Is it a Navel type orange? Sometimes it takes a few years for the plant to come into enough maturity to set and hold the fruits. . . . And dropping fruits is a common complaint with Navel Oranges. . . They set fruits and when the heat hits or the first dry wind and they slough off most, if not all their fruits. . . With time more and more will fruits will make it to maturity. . .. Most people are disappointed with the quantity of Navels but not the quality.   Terry Mikel