When applying basal bark treatments, which description is correct regarding carrier and placement?

• A. Applied with an oil carrier to the lower 15 inches of the trunk or brush stem, soaking to the ground line; usually with triclopyr plus 2,4-D
• B. Applied as a water-based spray to the canopy
• C. Injected into the trunk with a drill
• D. Ground-applied granules around the base

Answer: (A)

Basal bark treatment relies on delivering herbicide in an oil-based carrier to the lower portion of the trunk, up to about the ground line. The oil helps the mixture penetrate the bark’s surface so it can be absorbed into the living tissue and move systemically to kill the plant. Placing the treatment on the lower 15 inches around the trunk or brush stem and ensuring it soaks down to ground level targets the cambial area where uptake is most effective. Using a mix such as triclopyr with 2,4-D is common because it broadens the activity to many woody broadleaf species and provides good control of brush.

This approach differs from applying a water-based spray to the canopy, which wouldn’t stay on the bark or penetrate effectively, from injecting the trunk with a drill (a different method not used for basal bark), and from applying ground-based granules around the base (which is a soil treatment rather than a bark treatment).