It appears to be a buprestidae species. Not sure if spraying chemicals will help since the critters are boring under the bark, and if it is a buprestidae species then note its ability to metabolize toxic heavy metals, even living under tree bark soaked with arsenic or lead. The tree became a host for pathogens due to the bole damage, most of the time the tree will recover. Just let it take its course. BTW, what tree species, hackberry?