Are the white, fuzzy ones cottony cushion scale or mealy bug? There are photos at
http://www.ipm.ucdavis.edu/PMG... (cottony cushion scale photos)
and
http://www.entomology.umn.edu/... (citrus mealy bug photos)
Both sites have good information on these 2 types of pests.
You may want to try tanglefoot at the base of the tree to stop the ant parade. Ants frequently protect other pests so that they can "harvest" the honeydew - the tanglefoot should be effective in stopping them. Since I assume you are going to eat the fruit, I am hesitant to suggest an insecticide,,,,
Also, have you tried swabbing the scale and other pest with alcohol?
Please, let us know if either of the photos above are the right critter so you can get more definitive information.