Late blight disease of potato and its control measure

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Late blight disease of potato and its control measure

M.A. K. Mian, K.M. Khalequzzaman and N. Ara

Regional Agricultural Research Station, BARI, Ishurdi 6620, Pabna

Late blight is a serious disease of potato in Bangladesh. A huge yield loss occurred within very short time due to infestation of this disease. Experimental evidence indicated that yield loss was estimated about 25-50% due to infestation of this disease. Phytophthora infestans is the causal fungus for late blight disease of potato. At first water-soaked zigzag spots are appeared on tip and margin of leaves then spread to stem and tubers. Powdery white spores are visible under the infested leaves. Brownish ring spot are shown on the infested stem. Low temperature, fogy weather, high humidity and cloudy sky are favourable conditions for disease development.

The following measures can be applied for prevention and control of the disease:

1. Preventive measures:

a). Healthy seed should be used.

b) Irrigation must be stopped when disease incidence occurred.

c). Infested potato tubers should be removed during storage.

d). Harvesting of potato should be avoided at wet soil and after rains.

e). Harvested potato tubers should not covered with infested potato plants in the field.

f).Should cut and remove the potato plants at 85-90 days aged before harvesting.

2. Dithane M 45/Indofil (2 g/L of water) should be sprayed at 7 days intervals for preventive measure.

3. Prevailing of favourable weather for disease development:

a). Secure @ 2 g/L of water OR

b). Melodidew @ 2 g/L of water +Secure @1 g/L of water OR

c). Acrobat MZ @ 2 g + Secure @1 g /L OR

d). Acrobat MZ @ 2 g + Melodidew @1 g /L