They are seldom numerous and the damage to citrus trees is minimal. You can handpick leaves with egg masses from trees for some control. Pesticides are normally not used with this minor pest. A sapsucker is filling my sweet gum tree with holes. The pecking through the bark causes sap to flow from the wounds which attracts insects that the birds consume during return visits.
Most gardeners ignore sapsucker damage.
Trunks that appear to be severely affected could be encased in a fine mesh wire. Some gardeners also apply sticky bird repellents to trunks to discourage feeding. Crinum lilies are hardy plants. Though the tops are damaged, the bulbs should be fine. Pull or cut the dead portions from the tops of the bulbs and wait for new shoots to develop.