Late Blight
A destructive disease of tomato caused by the oomycete Phytophthora infestans, capable of destroying a crop rapidly in favorable conditions.
Affected Plant
Tomato
Severity
High
Symptoms
- Large, water-soaked, green-to-black lesions on leaves
- White fungal-like growth on leaf undersides in humid weather
- Firm, dark rot on fruit
Causes
- Spreads quickly in cool, wet weather
Prevention
- Choose resistant varieties where available
- Avoid overhead irrigation
- Maintain good plant spacing
- Destroy volunteer tomato and potato plants
Management
- Apply fungicide promptly at the first sign of disease
- Rapidly remove and destroy infected plants to limit spread
Related Tomato Diseases
Think your plant might have Late Blight?
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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.