Arborvitae spider mites (Eotetranychus thujae) are tiny pests that belong to the spider mite family. These arachnids feed on the sap of Arborvitae (Thuja) plants, which are commonly used as ornamental shrubs in landscaping. Spider mites have a piercing-sucking mouthpart that they use to extract nutrients from the plant’s cells, leading to discoloration, stippling, and sometimes even defoliation of the affected foliage.
The best way to treat Arborvitae spider mites is to follow these steps:
- Identify the Problem: Check for signs of spider mite infestation, such as discolored, speckled leaves, fine webbing, and overall poor plant health.
- Isolate Infested Plants: If you have multiple Arborvitae plants, isolate the infested ones to prevent the mites from spreading.
- Prune Affected Branches: Trim and remove heavily infested branches to reduce the mite population and improve air circulation.
- Spray with Water: Use a strong stream of water to wash off mites from the foliage. Repeat this regularly to disrupt their lifecycle.
- Apply Horticultural Oil: Spray a horticultural oil or insecticidal soap, following the manufacturer’s instructions. These products smother the mites without harming beneficial insects.
- Use Neem Oil: Neem oil is effective against spider mites and has minimal impact on beneficial insects. Apply according to label instructions.
- Introduce Predators: Release natural predators like ladybugs or predatory mites, which can help control the spider mite population.
- Maintain Proper Plant Care: Ensure the Arborvitae is well-watered and fertilized. Healthy plants are more resilient against pests.
- Regular Inspection: Monitor your plants regularly for any signs of re-infestation and take prompt action if needed.
Regular inspection and treatment for Arborvitae spider mites is included in an Arborscapes Plant Healthcare subscription along with countless other services and treatments. There is no better way to protect your living landscape. Have your yard be the envy of the neighborhood by subscribing today!
If you’re a DIY’er, remember a combination of these methods is often more effective than relying solely on one approach. Always read and follow the instructions on any product you use.
Chris is a Board Certified Master Arborist, Tree Risk Assessment Qualified, a North Carolina Licensed Landscape Contractor, Registered Consulting Arborist and a member of the American Society of Consulting Arborists. He has has 20+ years of experience in the industry, and currently serves as Vice President of the Southern Chapter of the ISA.