Gardeners grow orange trees because they love its delicious fruit. But orange tree owners soon discover they aren't the only ones in love with oranges. Orange trees attract a number of insects, including ants. However, it is unlikely that ants are living in your orange tree. More often, they are attracted to the food available in the orange tree. They may be farming aphids, scales or white flies to feed on their honey dew. Or they may be after the oranges themselves.
Wrap a thick band of a sticky ant trap such as Tanglefoot or horticultural glue around the trunk of the tree. Only the carpenter ant actually lives in trees. These ants only colonize the dead wood of heavily damaged or dead trees. The ants in the orange tree are climbing the tree from the ground up.
Monitor the sticky trap. Ants that touch the trap will become stuck and will eventually die. However, that won't stop more ants from trying to get to the tree. As more ants become stuck, they may create a "bridge" for other ants to cross. Check the sticky trap once weekly and brush accumulated ants off with a stick and replace the sticky trap as needed.
Prune branches that touch the ground, other plants or structures. Ants are problem solvers. Once their route up the trunk of the tree is blocked, they will likely seek other avenues to get to the food.
Lay ant bait traps around the base of the tree. This will lure the ants in your area to a more accessible food source. They will take the poisoned bait back to the colony and eventually kill it.
Horticultural glue is applied to the collar around the tree, which creates a sticky barrier that prevents the ants from climbing up the tree. This product has been used for more than 150 years.