Spruce Needle Loss in Maryland: Miners, Mites, and Horticultural Oil

Diagnosing and Treating Spruce Tip Feeders

Something eating needles off spruce tips in Maryland. Most common culprits: spruce needle miners (larvae mine inside needles) and spruce spider mites (suck sap, cause bronzing).

Identification Aid

TreeHelp.com has photos of each pest’s damage signature.

Control Options

• Horticultural oil (dormant or summer): Kills insects, mites, and eggs. Best overall. Apply per label (typically 1–2% summer, 3–4% dormant).
• Sevin (carbaryl): Broad-spectrum; kills beneficials; avoid during bloom.
• Pyrethrum/Rotenone: Organic contact killers; no residual; repeat needed.

Where to Buy

Oil, pyrethrum, rotenone available at garden centers or Gardens Alive.

Timing

• Miners: treat when new growth expands (larvae enter needles).
• Mites: monitor with white paper tap test; treat when 10+ mites per beat.