Weeping Willow Borer Infestation: Identification and Treatment

A weeping willow lost bark at the base with sawdust-like frass, holes, and ants. The culprit: wood borers.

Signs of Borers

Immediate: Spray trunk with permethrin (Onyx) or imidacloprid (Merit) to kill larvae under bark.
Next spring: Apply systemic imidacloprid (Bayer Advanced Tree & Shrub Insect Control) as a soil drench. Roots transport it to canopy; borers die when feeding.
Address stress: Borers attack drought-stressed willows. Water deeply—1 inch every 3 days without rain (use a pan under sprinkler to measure).

Trees: Weeping Willow with Bark Loss and Deformity: Internal Decay, Removal Advised; Weeping Willow Red Spiky Patches: Adventitious (Air) Roots, Not Borers—Harmless, Dry Up; Woodpecker Damage and Borer Infestation in Willow Trees; Borers in Weeping Willow: Signs and Management; Scale on Weeping Willow: Baking Soda Won’t Work—Use Proper Insecticide; Sapsucker Bird Damage on Curly Willow: Not an Insect Problem; Weeping Willow Decline: Roundup Drift vs. Borer Damage; Weeping Willow Near House & Drain: Root Concerns & Growth Regulators; Curly Willow (Corkscrew Willow): Unique Form for Year-Round Interest; Chinese Weeping Willow: History, Medicinal Uses, and Landscape Value

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