Cedar Apple Rust: A Fungal Infection in Apples
Cedar apple rust is a fungal infection that affects both the fruit and leaves of apple trees and crabapple trees. It is caused by the fungus Gymnosporangium juniper-virginianae.
Life Cycle of Cedar Apple Rust
Cedar apple rust has a unique life cycle that requires two different host plants: apple trees and juniper trees. In the spring, the fungus infects apple trees, causing the development of orange, gelatinous galls on the leaves and fruit. These galls produce spores that are released into the air and can travel up to 1,000 feet.
In the late summer, the spores infect juniper trees, causing the development of small, brown galls on the branches. These galls produce spores that are released in the spring and can infect nearby apple trees, completing the life cycle.
Symptoms of Cedar Apple Rust on Apples
- Orange, gelatinous galls on leaves and fruit
- Premature leaf drop
- Reduced fruit production
- Weakened trees
Damage Caused by Cedar Apple Rust
Cedar apple rust can cause significant damage to apple trees. Severe infections can ruin the entire crop. Even moderate infections can weaken trees and reduce fruit production.
Management of Cedar Apple Rust
There are several ways to manage cedar apple rust in apples:
- Remove or destroy nearby juniper trees. This is the most effective way to prevent infection.
- Monitor juniper trees for galls. If galls are present, destroy the plant or prune off and destroy the infected branches.
- Grow resistant apple varieties. Some varieties of apples are more resistant to cedar apple rust than others. Resistant varieties include Red Delicious, McIntosh, Winesap, and Empire.
- Use a fungicide spray. Fungicide sprays can be used to control cedar apple rust, but they are not always effective.
- Keep apple trees and juniper trees separated. Maintaining a distance of at least 1,000 feet between apple trees and juniper trees can help to prevent infection.
Prevention of Cedar Apple Rust
Prevention is the best way to control cedar apple rust in apples. By following the management practices outlined above, you can help to protect your apple trees from this damaging disease.
Additional Information
- Low levels of cedar apple rust infection may not significantly affect apple crops.
- Cedar apple rust is not harmful to juniper trees.
- Early detection and treatment of cedar apple rust is important to prevent severe damage to apple trees.
