Black Rot
A fungal disease of grape caused by Guignardia bidwellii, affecting leaves and fruit.
Affected Plant
Grape
Severity
Moderate to High
Symptoms
- Small brown circular leaf spots with dark margins
- Berries shrivel into hard black "mummies"
- Lesions may also appear on shoots and tendrils
Causes
- Fungal spores overwintering in mummified fruit and infected canes
- Warm, wet weather favoring spread
Prevention
- Remove mummified fruit and infected canes during dormant pruning
- Improve canopy airflow through proper training and pruning
Management
- Apply fungicide programs timed with grape growth stages per local extension guidance
Related Grape Diseases
Think your plant might have Black Rot?
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Diagnose Your PlantDisclaimer: This is an AI-generated result and not a replacement for expert agronomic or plant-pathology diagnosis. Confidence scores reflect the model's certainty, not biological ground truth. The model was trained and evaluated on leaf photos captured under controlled, lab-like conditions, so accuracy on real-world field photos (cluttered backgrounds, variable lighting, multiple or overlapping leaves) may be lower than the reported evaluation metrics.