What substance was injected into a tree cavity nest during documented government eradication efforts in North America?

Answer

Carbon dioxide ($ ext{CO}_2$)

In documented cases where a nest was found in a tree cavity, government teams plugged the nest, wrapped it in plastic, and injected carbon dioxide ($ ext{CO}_2$) to ensure the death of every hornet inside.

What substance was injected into a tree cavity nest during documented government eradication efforts in North America?
Predatorinsecthornetgiant hornet