Diagnosing and Treating Spider Mites and Leafminers in Arborvitae

Rust Color: Spider mite damage (unusually early).
Moths: Adult arborvitae leafminers.

Two Pests, One Stressed Hedge

2-year-old arborvitae turned rust-colored. Shaking reveals moths and spiders. Bi-weekly Miracle-Gro likely weakened plants.

STOP Fertilizing Every 2 Weeks: Excess nitrogen weakens tissue, invites pests.
Spray Miticide: For spider mites.
Spray Acephate or Permethrin: For leafminer larvae.

Fertilize only in spring and fall with balanced, slow-release formula. Water deeply but infrequently. Monitor for re-infestation.

Shrubs: Arborvitae Browning from Fertilizer Spikes: Salt Burn; Managing Daylily Rust and Aphid Infestations; Transplanting Lilacs in Prince George, BC with -5°C Nights; Moving Oleanders to a Heated Sunroom for Winter in London, Ontario; Reviving Sparse, Weak 'Endless Summer' Hydrangeas in Michigan; Nandina Hard Pruning: Clemson Recommends 1/3 Rule, Not Stumps; Rhododendron Rejuvenation Pruning: Staged or Drastic; Diagnosing Browning Arborvitae Planted Last Fall; Normal Interior Browning in Newly Planted Arborvitae; Fungicide Timing Critical: Prevention Beats Cure for Leaf Spot and Rust

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