A proud gardener puts enough time and effort into maintaining her crop that she should at least be able to enjoy it. If ants have decided that your citrus trees are a good place to frolic and forage for food, it can create problems. Ants tend to bring everyone they know with them when they take daily excursions, so rather than battling one ant you have to deal with thousands. Though greatly outnumbered, this battle is not yet lost. There are several things you can do to send ants on their way and save your citrus trees.
Add 6 tbsp. of sugar and 1 tsp. of boric acid to 2 cups of water. Stir the solution with a disposable plastic utensil to dissolve the sugar and boric acid. Dip cotton balls into the solution and place two or three of them into a small plastic container with a lid. Poke holes in the side to allow access for the ants and place it at the base of your tree. This toxic bait will attract and kill ants.
Wrap tape around the trunk of the tree with the sticky side facing out. As ants attempt to climb up it they will become stuck. Change out the tape every few days to discard immobilized ants.
Slice oranges or other pieces of fruit and scatter them underneath the tree. Ants will be pleased when they don't have to go as far to feast. When the birds notice the fruit they will fly down and pick it up, ants and all. If the birds don't come to get the fruit, discard the ant-covered fruit slices in a tightly sealed plastic bag.
Find the anthill and pour hot, soapy water into it. Both dish soap and hot water are bad for ants, so the combination will be deadly. Do this as often as needed to diminish your ant population.
Sprinkle black or cayenne pepper around the base of your tree to form a barrier that ants won't cross. This will help to protect your tree.