TOBACCO :: MAJOR DISEASE :: ANTHRACNOSE

Anthracnose -Colletotrichum tabacum
Symptoms
            Initially, infection starts on lower leaves as pale-brown circular spots of 0.5 mm diameter with papery depressed centres outlined by slightly raised brown margin. The leaf-spots may remain small with white areas in the centre or coalesce to form large necrotic lesions. Under continuous humid weather, dark brown or black, elongated, sunken necrotic lesions appear on midrib, petiole and stem resulting in petiole and stem rot. Such seedlings do not establish in the field if planted. Primary infection starts from affected bits of aerial parts left in the soil in the previous season. The pathogen is not seed-borne but persists in the soil on dried plant debris.
 
Management

• Raised seed beds and rabbing with farm wastes help in reducing the initial infection
• Removal and destruction of all diseased debris minimises the pathogen in the soil.
• Rogueing diseased seedlings especially with necrotic lesions on stem
• Protective spraying with Bordeaux mixture at 1.0% (2-2-500) or Zineb @ 2 kg/ha