Septoria leaf spot of Celery

Causal Agent:

• Pathogen: Septoria apiicola is a fungal pathogen responsible for causing Septoria leaf spot in celery.

Symptoms:

1. Leaf Lesions: Septoria leaf spot manifests as small, circular to irregularly shaped lesions on celery leaves.
2. Lesion Appearance: Lesions typically have a tan to brown center with a dark brown to purplish border.
3. Conspicuous Spots: As the disease progresses, the spots become more conspicuous and may coalesce.
4. Leaf Yellowing: Surrounding the lesions, there is often yellowing of the leaf tissue.

Disease Cycle:

1. Overwintering: The pathogen may survive on infected debris or volunteer celery plants.
2. Spore Production: The fungus produces spores on infected plant material.
3. Spread: Spores are spread by splashing water, wind, or human activities.
4. Infection: The spores infect new celery plants, leading to the development of new lesions.

Management:

Cultural Practices:

1. Crop Rotation: Rotate crops to break the disease cycle and reduce inoculum in the soil.
2. Sanitation: Remove and destroy infected plant debris to reduce overwintering sources.
3. Proper Spacing: Ensure proper plant spacing for good air circulation.

Fungicide Application:

1. Foliar Fungicides: Application of fungicides can be effective, especially during periods of high disease pressure.
2. Timing: Fungicides are often more effective when applied preventatively or at the early stages of disease development.

Resistant Varieties:

1. Plant Resistant Varieties: If available, consider planting celery varieties that are bred for resistance to Septoria leaf spot.

Regular Monitoring:

1. Scouting for Symptoms: Regularly inspect celery plants for early symptoms of Septoria leaf spot, especially during conditions conducive to disease development.

Weather Considerations:

1. Avoid Wet Conditions: Minimize overhead irrigation to reduce leaf wetness and create less favorable conditions for disease development.