A lot of people don’t like spraying toxic chemicals on any of their plants and particularly not on plants where they’re going to eat the produce, like a citrus tree in this case.
One of the alternatives to using sprays is using a yellow sticky trap, basically a yellow board covered with a sticky substance hung near the tree. The bright yellow colour attracts the insects and they get stuck as they land on the sticky coating and then the insect eventually dies. Replace the card when it is covered in insects, or when it is no longer sticky. Much better than using toxic sprays.