It is present in both hills & plains. Brownblack necrotic spot-angular, oval shapecharacterized by concentric rings .Several spot coalesce & spread all over the leaf. Shot holes on fruits. Hyphae are light brown or olivaceous which become dark coloured with age. Hyphae are branched, septate and inter and intra cellular. Coniophores emerge through the stomata or between the epidermal cells. Conidia are club shaped with a long beak which is often half the long of the whole conidium. Now the lower part of the conidium is brown while the neck is colorless. An body of the conidium is divided by 5 – 10 transverse septa and there may or may not be a few longitudinal septa.
Early blight Favourable condition
Dry warm weather with intermittent rain .Poor vigor. Temperature: 25-30°C. Poorly manured crop.
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Mode of spread and survival
Conidia and mycelium in the soil or in the detritus of afflicted plants can survive for more than 17 months. These conidia, or the fresh conidia discovered on the overwintered mycelium, cause the initial infection of the subsequent potato crop. Secondary infection plays a larger role in disease transmission. Because the conidia that grow on the spots generated by the first infection are disseminated across long distances by wind. Rain and insects may transmit the conidia from the infected plant to other plants.
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Early blight Management
When sowing, utilize disease-free seed tubers. Since soil-dwelling spores are the principal source of infection, any infected plant debris must be removed and destroyed. Zineb or captan 0.2% can be used very early in the day and then repeated every 15 to 20 days to establish effective management. The Kufri Sindhuri variety exhibits modest hardiness.
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