Hot and humid climates are favourable for the occurrence of this disease.
Damage Symptoms:
White tiny dots appear on the top of the leaves, and areas of chlorosis are present at the tip region. The tips of the leaves die, dry out, and break off at the point of infection, causing them to droop down.
In the chlorotic region, circular to oblong brown velvety concentric rings are formed.
These lesions expand towards the bottom of the leaves. The leaves gradually die from the tip downwards.
Softening of the fleshy scales that encase the bulb and wrinkling of the scales, eventually turning them dry and thin.
Preventive Measures:
Seed treatment with Thiram @ 2.5g/kg of seed can be done.
Control Measures:
Three sprays of 0.25% Copper Oxychloride, 0.2% Chlorothalonil, 0.2% Zineb, and 0.2% Mancozeb can be applied.
