Oranges, especially navels, have been afflicted with a necrotic spotting this winter. The spots are typically irregular to round and usually smaller than a dime. The lesions are dark brown and slightly depressed.
Affected fruit are normally at or below waist level in the tree.
Navels, Marrs and other oranges have been reported with damage, but grapefruit does not seem to have the problem. The damage has been erroneously called leprosis, but is more appropriately referred to as exosis or nail-head rust, since leprosis is a disease. The culprit has been identified as false spider mites by Dr. Vic French of the Citrus Center and confirmed by Dr. Carl Childers of the University of Florida. In fact, Dr. Childers came over from Florida last week to survey the situation in person and to present a seminar on Brevipalpus and some of the diseases associated with this mite. More on that later.