Pia, I have no idea what 'Flogtribus' is but 'Kalokori' sounds like a bug that used to be known as Calocoris but is now, I believe, called Closterotomus trivialis. They are known to attack olive, citrus and some prunus species, especially the young growth. However, their preferred hosts would appear to be a variety of weeds such as nettles, etc. Unless the infestation is very severe I doubt that they will actually kill the tree. Suggestions for control seem to range from leaving weeds in situ in the area of the trees, especially during bud break and flowering, to spraying with an insecticide. Ones containing malathion are popular here in Cyprus. Personally I never spray with anything but I've not found this particular bug to be a problem.