Assuming that you are treating carpenter ants, you can apply
Bora-Care to any areas that have an active infestation of powder post beetles, termites or carpenter ants. It will need to be treated at the rate of 1:1 and all other areas where there is no activity can be used 5:1. Once the Boracare has been applied to the fence, you will need to seal/stain/paint it to keep the rain from slowly washing it away over the years. If sealed, the Boracare will last for the life of the wood after application. Please let us know if you have any other questions.