Hi there!

Do you have a black locust tree or honeylocust tree? There is a locust borer, which attacks black locusts, and a honeylocust borer, which attacks honeylocusts. Locust borers create round exit holes in the tree and can be managed by spraying the tree with Carbaryl (Sevin) in the mid to late summer (https://entomology.wsu.edu/outreach/bug-info/locust-borer/). Honeylocust borers, on the other hand, create D-shaped exit holes (which I think is what I'm seeing on your tree, but am not positive due to the angle of the photo). Honeylocust borers are a secondary pest that attack stressed trees, often concentrating in areas where there are wounds or cankers. The boring holes you found do seem to be concentrated in a damaged area since part of the bark is absent (potentially due to sunscald?), so this would make sense. Because honeylocust borers are a secondary pest, the best way to manage them is to correct any factors that may be stressing the tree (keep tree well watered, prevent additional injury, etc.). An insecticide, like Permethrin, can be applied on the trunk in the early summer, but this should be considered supplemental treatment to appropriate cultural care and not the primary treatment (https://extension.usu.edu/pests/ipm/ornamental-pest-guide/arthopods/wood-borers/honeylocust-borer and https://extension.colostate.edu/topic-areas/insects/insect-and-mite-pests-of-honeylocust-5-571/). Alternately, soil drench applications of imidacloprid can be effective if applied in spring to trees not already
damaged badly by borers.

Let me know if you have further questions!

Hania