Copper Fungicide for Spruce Blight: Timing & Limits

A reader in Oklahoma City asked if copper fungicide cures blight on spruce and evergreens, and application frequency.

The expert explained copper only prevents new infections—it doesn't cure existing cankers. Apply as new growth buds out, then every 10 days until no new foliage emerges (mid-July). Wet weather increases blight. Infected foliage will brown and drop regardless.

Spray Schedule

• Start at budbreak.
• Repeat every 10 days.
• Stop when new growth hardens off (mid-July).
• Copper protects new needles only.