Stone fruit rust

Tranzschelia discolor:

Tranzschelia discolor is a fungal pathogen responsible for causing cherry leaf spot, a disease that affects cherry trees. Here's an informative description:

Symptoms:

1. Leaf Lesions: The disease manifests as small, dark lesions on the upper surface of cherry leaves.
2. Yellow Halos: Lesions may have yellow halos surrounding them.
3. Leaf Deformation: Severely infected leaves can become distorted and exhibit a puckered appearance.
4. Premature Leaf Drop: Advanced infections may lead to premature defoliation, reducing the tree's overall vigor.

Identification:

1. Leaf Inspection: Regularly inspect cherry tree leaves for the presence of small dark lesions with or without yellow halos.

Disease Cycle:

1. Overwintering: The fungus survives the winter on infected leaves and twigs.
2. Spore Production: In spring, spores (aeciospores) are produced on overwintered leaves.
3. Infection: Spores are disseminated by wind and rain, infecting new leaves.
4. Secondary Infections: Secondary infections occur throughout the growing season, producing urediniospores.

Management:

Cultural Practices:

1. Pruning: Prune cherry trees to improve air circulation and sunlight penetration, reducing humidity.
2. Sanitation: Remove and destroy infected leaves to reduce the source of inoculum.

Chemical Control:

1. Fungicide Application: Application of fungicides, especially in the spring when new leaves are emerging, can help manage cherry leaf spot.

Regular Monitoring:

1. Scouting for Symptoms: Regularly monitor cherry trees for early symptoms of cherry leaf spot, especially during periods conducive to disease development.

Resistant Varieties:

1. Choose Resistant Varieties: Plant cherry tree varieties that are resistant or less susceptible to cherry leaf spot.

Post-Disease Practices:

1. Fall Cleanup: Remove fallen leaves and debris in the fall to reduce overwintering sites for the fungus.