DOWNY MILDEW OF BAJRA
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This document summarizes downy mildew of bajra or pearl millet. It affects crops grown in Africa and India, causing epidemics in 1970 and 1983. Symptoms appear as light green or yellow patches on leaves and ear heads. The fungus has non-septate, intercellular mycelium and elliptical sporangia. Oospores remain in soil for 5 years and cause primary infection in seedlings. Secondary infection occurs via sporangia. Favorable conditions for the fungus include high humidity, leaf moisture, and temperatures of 15-25 degrees Celsius. Management strategies include using healthy seed, removing infected plants, crop rotation, resistant varieties, and fungicide seed treatments or sprays.
DOWNY MILDEW OF BAJRA
- 1. DISEASES OF FIELD CROPS AND THEIR MANAGEMENT DOWNY MILDEW OF BAJRA OR PEARL MILLET
- 2. ECONOMIC IMPORTANCE • It is mainly grown in Africa and India as well. • This was first reported by Butler in 1907 • Disease is severe in ill drained and low lying areas. • The disease occurred in epidemic form in 1970 and 1983 devastating the popular hybrids HB3 and BJ 104.
- 3. Disease Symptoms • Infection is mainly systemic and symptoms appear on the leaves and the ear head. The first symptoms can appear in seedlings at three to four leaf stage. • The affected leaves show patches of light green to light yellow colour on the upper surface of leaves and the corresponding lower surface bears white downy growth of the fungus
- 6. Pathogen • The mycelium is systemic, non-septate and intercellular in parenchymatous tissues. • Sporangia are hyaline, then walled and elliptical. • Oospores are round in shape, surrounded by smooth thick walled yellow brown wall.
- 7. Disease Cycle • The oospores remain visible in soil for 5 years to rise the primary infection on host seedling. • Primary infection by oospores. • Secondary infection is by sporangia. • The pathogen readily infects teosinte and Setaria Italica.
- 9. Favorable Conditions • Relative humidity should be very high (90%). • Presence of water on leaves. • Low temperatures of 15-25 degree Celsius. • These conditions favors formation of Sporangiophores and Sporangia.
- 10. Management • Selection of healthy seed. • Collect diseased plants before the formation of oospores and burn them. • Summer deep ploughing. • Roughing the infected plants. • Crop Rotation. • Grow resistant varieties like WCC 75, PHB 10, ICMH 45, PHB 14. • Treat the seeds with Metalaxyl or Captan @ 49/kg. • Spray Mancozeb @ 0.25% from 30 daays after sowing.
- 11. Presented By: Name: Naga Harshitha Goud UID: 111718012014