Late Blight
A destructive disease of potato caused by the oomycete Phytophthora infestans, historically associated with the Irish potato famine.
Affected Plant
Potato
Severity
High
Symptoms
- Water-soaked, pale-to-dark green lesions on leaves that rapidly turn brown or black
- White, fungal-like growth on leaf undersides in humid conditions
- Firm brown rot of tubers
Causes
- Spreads rapidly in cool, wet weather via windborne and waterborne spores
Prevention
- Use certified disease-free seed potatoes
- Choose resistant varieties where available
- Destroy volunteer potato plants
- Avoid overhead irrigation
Management
- Apply fungicide promptly at the first sign of disease
- Remove and destroy infected plants quickly to limit spread
Related Potato Diseases
Think your plant might have Late Blight?
Upload a photo of the affected leaf and get an instant AI diagnosis with a Grad-CAM explanation of what the model saw.
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.