How do I distinguish early blight from late blight in potato and manage each?
Difference between early blight and late blight in potato (aloo) and how to tell them apart?
RRajendra1yr ago · 427 views
3 Answers
🌾Farmer.in Krishi TeamExpert ✓1yr ago
They are different diseases with different looks and timing. Early blight (Alternaria) shows brown spots with concentric rings, a target board pattern, usually on older lower leaves, and is worse in warm weather and on stressed or nutrient short plants. Late blight (Phytophthora) shows dark, water soaked, rapidly spreading patches, often with a white downy growth on the leaf underside in humid weather, and thrives in cool, cloudy, wet conditions, killing the crop fast. Manage early blight with mancozeb or chlorothalonil and good plant nutrition; manage late blight with protective mancozeb plus a systemic like metalaxyl when pressure is high. For both, use healthy seed, rotate crops, ensure airflow, avoid evening overhead irrigation, and rotate fungicide groups. Follow the label and pre harvest interval on any fungicide.
SShyamlal1yr ago
The target board rings are the giveaway for early blight. Once I learned to look for those concentric circles on the lower old leaves I stopped confusing the two and spraying the wrong thing.
MMahesh1yr ago
If you are not sure, the speed tells you. Late blight in cool foggy weather races across the field in a day or two and smells off, while early blight creeps along slowly. When in doubt take a leaf to the KVK before buying an expensive systemic.