I have satsuma trees in the back. I have one orange tree. A few years back something killed all the leaves and all the branches off the orange, did not touch the satsumas. The tree has a large strong trunk (4 or 5 inches by 5ft) and has been trying yearly to bring out branches and leaves and it blossoms 100's and 100's of blooms. Then all the tiny fruits disappear, I assume they fall off but I don't see any on the ground. Then most of the leaves and branches fall off and it is dormant till next spring. The only thing I can imagine was maybe the spray used in the cane fields were affecting it, but it should mess with the Satsumas also. Then I thought maybe its too many blooms for the little plant to handle. I have not tried pruning because the longest branch I have seen in 5 or 6 years is only probably less than 2 ft. long. When it first happened I did prune back the dead. Any citrus experts out there have an opinion?