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Late Blight of Potato. Description: This disease caused by fungus called Phytophthora infestans . The disease may attack almost any time after the crop has put up a fairly good foliage . Initially the lower leaves infected. Symptoms: They show water-soaked lesions especially towards margins.
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Late Blight of Potato Description: • This disease caused by fungus called Phytophthora infestans. • The disease may attack almost any time after the crop has put up a fairly good foliage. • Initially the lower leaves infected. Symptoms: • They show water-soaked lesions especially towards margins. • The spots enlarge if proper humidity and temperature are a available..
In humid atmosphere, the growth of the fungus can be seen on lower side of these spots as whitish cottony growth. • The spot turn black as the affected leaves start rooting. • Similar symptoms may be observed on stems also. • Decaying leaves often omit offensive odour. • The tubers under the ground also decay before harvest. • On tubers greenish sunken area may be seen.
Management • Use potato tubers for seed from disease free areas to ensure that the pathogen is not carried through seed tuber . • Spray Metalaxyl formulations like Ridomil MZ or Motco or Krilaxyl at the rat of 2 gram/liter water when whether is congenial and continuous fog and intermittent rains. Spraying should be repeated at 10-15 days interval. • The infected plant material in the field should be properly destroyed. • Grow resistant varieties like Kufri Jawahar, Kufri Chipsona-1, Kufri Chipsona-2, Kufri Sutalj etc.