What Is The Orange(fruit) Florida Orange Tree, Fruit Is Failing To Mature?

Florida orange tree, fruit is failing to mature? - what is the orange(fruit)

My mother had an orange and ruby grapefruit tree in St. Augustine (North Florida) for about 4 years without any problems of fruit development. But in the last year and this year the result of two trees that are at opposite ends of the morning-garden size, not matured. This is definitely pollination by bees (such as the fruit grows a little, showing that the bees pollinate it is), and my mother is an avid gardener, with particular attention to your plants - not enough over or under irrigation, fertilization, so that I asked if anyone has experienced a similar situation with citrus in Florida this year? She is in contact with the department of local agriculture, but say there is a problem with pollination, which is not the case because the fruit grows and not something like a fall of dust produced fruit. Any help would be very grateful! Thank you!