Tobacco Streak Virus (TSV) is a plant virus of the Bromoviridae family and the genus Ilarvirus. It has a diverse host range, with over 200 vulnerable species, and is most harmful in warm, tropical areas. TSV does not usually produce broad outbreaks, although it can cause severe damage to sunflowers, cotton in India and Australia, and peanuts in India. TSV infects plants via wounds and can produce symptoms such as leaf yellowing and stunting, decreased blooming and boll output, and leaf necrosis.
Tobacco Streak Virus Management in Cotton
The Causal Organism of Tobacco Streak Virus
Tobacco Streak Virus (TSV) is the causative agent of a plant disease that affects a variety of plant hosts, including tobacco, asparagus, strawberries, soybeans, and sunflowers. Infected seeds are the primary source of infection. Secondary transmission from plant to plant occurs by vector pests (aphids or thrips) or mechanical harm to the plants during field operations.
The Disease Cycle of Tobacco Streak Virus
TSV (Tobacco Streak Virus) is an ss-RNA virus that infects cotton plants and causes harm to yield and plant growth. Spheroid particles of coat protein subunits encase an ss-RNA genome. The coat protein components are important in the virus’s life cycle, preserving the viral DNA and permitting cell-to-cell migration. Once within the host cell, the virus uncoils and releases its viral genomic RNA into the cytoplasm, where it is reproduced and expressed.
The new virus particles are then constructed when the dsRNA genome is produced from the genomic ssRNA. TSV may infect cotton plants by various routes, including thrips vectors, mechanical injury, pollen, or dodder. It requires a live plant to survive, and once systemic, it may cause considerable crop damage.
Causes/conditions Favorable for Tobacco Streak Virus Disease Spread in the Field.
- TSV causes yellowing and stunting of leaves, decreased blooming and boll development, and leaf necrosis in infected plants, resulting in poorer yields and plant growth.
- The severe symptoms of disease and their impact on yield are determined by plant type, climatic circumstances (temperature and humidity), and the plant’s growth stage when infected.
- TSV spreads in the field via infected seeds and vector pests like aphids and thrips. Warm and humid surroundings, as well as late infestations by aphids, are ideal for the spread of TSV illness.
Symptoms of Tobacco Streak Virus Disease
- Cotton plants are affected by Tobacco Streak Virus Disease, which produces a variety of symptoms. The following are the major symptoms to look out for:
- Small chlorotic patches: Infected plants first exhibit tiny, uneven yellow or discolored spots on the leaves approximately 2-5 mm in diameter.
- Large angular chlorotic or necrotic patches get larger over time, ranging in size from 5 to 15 mm in diameter, and produce an uneven mosaic pattern on the leaves.
- Leaf necrosis and early shedding: Necrotic leaves may fall off prematurely, resulting in a lower canopy and stunting of the plant.
- Reduced flowering and boll drop: The quantity of flowers on infected plants is reduced, and bolls may drop off early, decreasing yields significantly.
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