Tobacco Powdery Mildew: Erisiphe cichoracearum var nicotiane
Symptom:
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Initially greyish white spots (about 0.5-lcm in diameter) appear at the base of the lower leaves of the maturing plant.
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Under favourable conditions of low temperatures (16° -23° C) and high humidity these white patches spread to upper leaves, enlarge and cover the entire surface of the leaf.
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Such leaves on curing get scorched and show brown patches rendering them unfit for marketing.
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Sometimes leaves with incipient infection result in blemished on curing which reduce the commercial value of leaves.
Management:
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Avoiding over fertilizing, overcrowding of plants and removal of affected basal leaves will help in minimizing primary infection and spread of the disease.
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Early planting to escape cool temperature prevalent at the maturing stage will also reduce the incidence.
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Apply sulphur powder (200 mesh) @ 40 kg/ha to the soil between plant row 6-8 weeks after planting. Mix ash or sand to sulphur for easy application.
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See that sulphur does not fall on tobacco leaves. Recommended for black soils only.
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Spray 0.2% Karathane or Thiovit or 0.05% Carbendazim just before the disease sets in Repeat at 10-12 days interval if necessary
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Use resistant varieties like Swarna or Line 2359 developed at Central Tobacco Research Institute, in disease endemic area.
Source-
- TamilNadu Agritech Portal
