📈 Diseases of Tobacco and Jute

Tobacco and jute are quality-sensitive crops where even moderate disease incidence can cause major losses in market value. Accurate symptom recognition and sanitation-based management are central for both crops.

Tobacco Diseases

Tobacco Mosaic Disease

Causal organism: Tobacco mosaic virus (TMV) — one of the most extensively studied plant viruses

Symptoms

• Light and dark green mosaic pattern on leaves
• Leaf curling, distortion, and reduced leaf size
• Stunting in early-infected plants
• Blistering and puckering of leaf lamina

Transmission and Disease Cycle

• TMV is extremely stable — survives in dried plant debris for years
• Primarily transmitted by mechanical contact (hands, tools, transplanting)
• NOT transmitted by insect vectors (unlike most plant viruses)
• Very high concentration in plant sap (10 mg/L)

Management

• Cross-protection using mild TMV strains
• Wash hands with milk or tri-sodium phosphate before handling plants
• Resistant/tolerant varieties
• Strict sanitation — avoid tobacco use in nurseries and fields

Black Shank

Causal organism: Phytophthora nicotianae var. nicotianae

• Dark brown to black lesion at stem base extending upward
• Pith turns black in disc-like plates
• Root rot and wilting of entire plant
• Management: Resistant varieties, Metalaxyl application, avoid waterlogging

Brown Spot

Causal organism: Alternaria alternata

• Circular brown spots with concentric rings on mature leaves
• Reduces leaf quality significantly (curing quality affected)
• Spray Mancozeb (0.2%) at disease onset

Jute Diseases

Stem Rot

Causal organism: Macrophomina phaseolina

Symptoms

• Dark brown to black lesions on stem at soil level
• Stem becomes dry and brittle with black sclerotia visible inside
• Plants show wilting and break at the base
• Fibre quality severely affected

Management

• Seed treatment with Carbendazim (2 g/kg)
• Crop rotation with rice or non-host crops
• Trichoderma viride soil application

Anthracnose

Causal organism: Colletotrichum corchorum

• Dark brown, sunken lesions on stem, petiole, and leaves
• Stem lesions crack and expose fibre, reducing quality
• Spray Copper oxychloride (0.3%) at disease onset

Soft Rot

Causal organism: Sclerotium rolfsii

• Soft, watery rotting of stem at base with white mycelial growth
• White to brown round sclerotia visible on affected tissue
• Crop rotation and deep ploughing to bury sclerotia

Summary Cheat Sheet