Question: What is this on my citrus and why are ants always
Answer: The structures on the limbs are scale insects
sucking the sap from the tree and should be eliminated by spraying
a summer oil spray or Neem Oil Spray. The ants tend to the "herd"
scales (usually brown soft scale), moving the younger (mobile
new areas to feed, and protecting all of them from predators.
surprisingly, there is very little sooty mold (black substance
surface) associated with these scales because the ants keep the
(excrement or secretions of the sucking insects) pretty well cleaned