Overview
Found on an Ash tree. Credit to @andrewcannon for noticing that this Ash Rust specimen is hosting a parasitic Tuberculina fungus (lilac colored) and larva of a Mycodiplosis midge (orange colored). I will link the two associated observations.
- Type
- Fungus
- Severity
- MODERATE
- Source
- iNaturalist
Symptoms
Geographic Spread
Treatments
Fungicide Application
Apply systemic or contact fungicide at the first sign of infection. Repeat applications may be needed during wet weather. Follow label rates and timing.
Sanitation and Pruning
Remove and destroy all infected leaves, branches, and fallen debris. Improve air circulation by thinning dense canopy growth. Sterilize pruning tools.
Soil and Moisture Management
Ensure proper drainage, avoid overwatering, and apply mulch to reduce soil splash. Many fungal pathogens thrive in persistently wet conditions.
Recommended Products & Tools
Helpful supplies for managing ash rust. Always read and follow label directions, and confirm a diagnosis before treating.
Broad-spectrum protectant for many fungal leaf and bark diseases.
Preventive spray for needle cast, leaf spots, and blights.
Sharp, clean cuts to remove affected wood — a tree-care essential.
As an Amazon Associate, TreeIssues may earn a commission from qualifying purchases made through these links — at no extra cost to you.
Frequently Asked Questions
What is ash rust?
Found on an Ash tree. Credit to @andrewcannon for noticing that this Ash Rust specimen is hosting a parasitic Tuberculina fungus (lilac colored) and larva of a Mycodiplosis midge (orange colored). I will link the two associated observations.
What are the symptoms of ash rust?
Where is ash rust currently found?
ash rust is currently active in Minnesota. It has been reported in 1 total state across the United States.
How do I treat ash rust?
Treatment options for ash rust include: Fungicide Application, Sanitation and Pruning, Soil and Moisture Management. Treatment approaches may include chemical, biological, cultural, and mechanical methods depending on the severity and context.