Issues in Choosing an Insecticide For Borers
Because borers spend most of their time safely hidden in tunnels inside plant stems or branches, they are rarely harmed by chemical insecticides sprayed on plant surfaces. However, borers eventually turn into moths and beetles and emerge at certain predictable times, varying according to their species.

In some cases, when other trees in an area need protection, a professional arborist will know when to spray a tree and what insecticide material to use to kill the adult stages of borers.