Pest identification
What's eating my arborvitae?
Spider mites
Signs: Foliage turns bronze, yellow, or brown from the inner branches outward; fine webbing may be visible in dry, heated indoor air.
Control: Increase humidity with a pebble tray or humidifier; mist foliage and treat with neem oil or a miticide spray every 5–7 days for 3 cycles.
Scale insects
Signs: Small waxy or brown bumps on stems and foliage; needles turn yellow and drop; honeydew makes surfaces sticky.
Control: Scrape off visible scales; apply horticultural oil spray, covering all surfaces. Repeat after 2 weeks. Improve air circulation around the plant.
Bagworms (if moved outdoors)
Signs: Spindle-shaped silk-and-foliage bags hanging from branches; defoliation of entire branch tips as larvae feed inside.
Control: Handpick and destroy bags in winter before eggs hatch; apply Bt (Bacillus thuringiensis) spray in late spring when larvae are young.
Keep arborvitae pest-free
Healthy plants resist pests best. Get the basics right:
Arborvitae pests — FAQ
What is eating my arborvitae?
Arborvitae grown as a houseplant faces mainly spider mites and scale insects indoors, though bagworms and deer are serious threats when grown outdoors. Indoors, dry air fuels spider mite explosions, making them the primary risk. Inspect the fine foliage carefully — damage is easily missed until it is extensive.
How do I get rid of spider mites on arborvitae?
Foliage turns bronze, yellow, or brown from the inner branches outward; fine webbing may be visible in dry, heated indoor air. Increase humidity with a pebble tray or humidifier; mist foliage and treat with neem oil or a miticide spray every 5–7 days for 3 cycles.
How do I get rid of scale insects on arborvitae?
Small waxy or brown bumps on stems and foliage; needles turn yellow and drop; honeydew makes surfaces sticky. Scrape off visible scales; apply horticultural oil spray, covering all surfaces. Repeat after 2 weeks. Improve air circulation around the plant.
How do I get rid of bagworms (if moved outdoors) on arborvitae?
Spindle-shaped silk-and-foliage bags hanging from branches; defoliation of entire branch tips as larvae feed inside. Handpick and destroy bags in winter before eggs hatch; apply Bt (Bacillus thuringiensis) spray in late spring when larvae are young.