Tulip Tree Root Collar Borer: Onyx Trunk Spray

Holes at base of 6-year tulip tree = root collar borer (Euzophera ostricolorella). Not necessarily fatal if treated.

Treatment

• Onyx (bifenthrin) 0.25 fl oz/gal water.
• Spray trunk base to 3 ft up—thoroughly wet bark.
• 1–4 gal per tree.
• Repeat every 3 months spring–summer for prevention.

Why Onyx

• Kills active borers + prevents new attacks.
• Long residual on bark.
• Professional product; may need licensed applicator or online source.

Alternatives

Permethrin or carbaryl trunk sprays (shorter residual).

Act now—borers girdle and kill fast at root collar.