To treat scale on the orange tree I used white oil and then tangle foot. The evening before I sprayed the oil onto the tree with a hose attachement. The morning following I wrapped the trunks with paper towel and then with duck tape (over the towel). On top of the duck tape I smeared TangleFoot.
Update: the day after the ants had found a path under the paper towel. I crammed some cotton in the gap and this took care of the problem.
Update: now two weeks out (and after a few rains) still now ants are traveling up the trunk for farm the scale :-)
