Cedar-Apple Rust
MODERATEGymnosporangium juniperi-virginianae
Overview
A fungal disease requiring two hosts to complete its life cycle: eastern red cedar (juniper) and apple or crabapple trees. It causes economic losses in apple orchards and aesthetic damage to landscape cedars.
- Type
- Fungus
- Severity
- MODERATE
- Source
- iNaturalist
Symptoms
Bright orange gelatinous spore horns on cedar galls in spring, yellow-orange spots on apple leaves and fruit, premature leaf and fruit drop on apples, round brown galls on cedar branches
Affected Species
Geographic Spread
Treatments
Remove Nearby Junipers
Eliminating eastern red cedar and other juniper species within a few hundred yards of susceptible apple trees breaks the disease cycle. Impractical in some landscapes.
Fungicide Spray Program
Preventive application of myclobutanil or mancozeb fungicide to apple trees from pink bud through petal fall and beyond. Timing based on weather conditions and spore release.
Recommended Products & Tools
Helpful supplies for managing Cedar-Apple 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 Cedar-Apple Rust?
A fungal disease requiring two hosts to complete its life cycle: eastern red cedar (juniper) and apple or crabapple trees. It causes economic losses in apple orchards and aesthetic damage to landscape cedars.
What are the symptoms of Cedar-Apple Rust?
Bright orange gelatinous spore horns on cedar galls in spring, yellow-orange spots on apple leaves and fruit, premature leaf and fruit drop on apples, round brown galls on cedar branches
Where is Cedar-Apple Rust currently found?
Cedar-Apple Rust is currently active in Alabama, Arkansas, Connecticut, Delaware, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Massachusetts, Maryland, Maine, Michigan, Minnesota, Missouri, Mississippi, North Carolina, Nebraska, New Hampshire, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Virginia, Vermont, Wisconsin, West Virginia, Montana. It has been reported in 34 total states across the United States.
What plants are affected by Cedar-Apple Rust?
Cedar-Apple Rust affects Eastern Red Cedar, Apple, Rocky Mountain Juniper. Susceptibility varies by species.
How do I treat Cedar-Apple Rust?
Treatment options for Cedar-Apple Rust include: Remove Nearby Junipers, Fungicide Spray Program. Treatment approaches may include chemical, biological, cultural, and mechanical methods depending on the severity and context.
Compare with Similar Ailments
Not sure if it's Cedar-Apple Rust? Compare it side-by-side with similar ailments.