Causal organism: Tobacco Mosaic Virus (TMV).
Origin
Adlof Mayer at first reported this disease in 1886. In 1892 Iwanowski demonstrated that the tobacco mosaic virus would pass through a bacteriaproof filter. It is the first reported viral disease in the world. It has a long association with other viral diseases.
Symptoms and Management of Tobacco Mosaic Virus
Symptoms and Management of Tobacco Mosaic Virus are given below.
Symptoms
- Discolored vein/Yellowing of the vein of the leaf.
- Green patches and yellow patches are alternate with each other. This is the most characteristics symptom of leaf mosaic of tobacco.
- Three types of characters such as mottling, distortion, and Stunting are seen on the leaves.
- Infected bud leaves become twisted and malformed.
- If infection makes earlier, severe dwarfing of plant reduced yield and reduction yield quality.
Favorable condition
- Excess use of nitrogenous fertilizer.
- Windy weather.
- Insect infestation.
- Present of wounds.
Intensity of disease
The intensity of disease depends on the physical and environmental conditions. The virus can survive in dried tobacco leaves up to 5 years and infected plant juice up to 25 years.
Transmission
TMV transmitted by sap. It is done mechanically (Animal, knife, labor hands, etc).
Control Measure
- Field sanitation.
- Highly contagious disease; washed the used implements as well as labor hands by running water.
- Roughing and cultural practices.
- Seedbed soil should be sterilized by steam.
- Destruction of the collateral host.
- Balanced fertilizers are used (optimum Nitrogenous fertilizer).
- No chemical is recommended for TMV.