Model Answer
0 min readIntroduction
Tomato leaf curl and mosaic diseases are significant biotic constraints impacting tomato production worldwide, causing substantial yield losses. Leaf curl disease, primarily caused by begomoviruses transmitted by whiteflies, and tomato mosaic virus (ToMV), a member of the tobamovirus family, are prevalent. These diseases affect both small and large-scale tomato cultivation, impacting food security and farmer livelihoods. Understanding the symptoms and implementing effective management strategies are crucial for sustainable tomato farming. The incidence of these diseases has been increasing due to factors like climate change and increased use of pesticides which kill beneficial insects.
Leaf Curl Disease in Tomato
Leaf curl disease is a complex viral disease affecting tomato plants, primarily caused by various begomoviruses. These viruses are transmitted by whiteflies (Bemisia tabaci).
Symptoms
- Severe curling and twisting of leaves, upward and inward.
- Stunted plant growth and reduced vigor.
- Yellowing of leaves (chlorosis).
- Failure to flower or production of deformed flowers.
- Reduced fruit set and small, misshapen fruits.
Management
- Cultural Practices: Crop rotation, timely weeding, and destruction of infected plants.
- Resistant Varieties: Use of tomato varieties with resistance or tolerance to leaf curl viruses.
- Vector Control: Control of whitefly populations through yellow sticky traps and insecticides.
- Biological Control: Introduction of natural enemies of whiteflies like ladybugs and lacewings.
- Hygiene: Sanitize farm tools and equipment to prevent virus spread.
Tomato Mosaic Virus (ToMV)
Tomato mosaic virus (ToMV) is a highly contagious virus belonging to the Tobamovirus genus. It affects a wide range of solanaceous crops, with tomato being a primary victim.
Symptoms
- Mosaic pattern on leaves – light and dark green patches.
- Stunting of plant growth.
- Leaf distortion and mottling.
- Brown, necrotic spots on leaves.
- Reduced fruit size and quality; fruit may be blotchy.
Management
- Cultural Practices: Crop rotation with non-solanaceous crops.
- Resistant Varieties: Planting resistant tomato varieties (e.g., those carrying the Tm-1 gene).
- Hygiene: Strict sanitation of farm equipment and structures. ToMV is highly persistent in soil and on surfaces.
- Source of Clean Seedlings: Using certified disease-free seedlings.
- Vector Control: While ToMV is not transmitted by insects, controlling mechanical spread is key.
| Feature | Leaf Curl Disease | Tomato Mosaic Virus (ToMV) |
|---|---|---|
| Causative Agent | Begomoviruses (transmitted by whiteflies) | Tobamovirus |
| Primary Symptoms | Leaf curling, stunting, yellowing | Mosaic pattern on leaves, stunting, blotchy fruit |
| Vector | Whiteflies (Bemisia tabaci) | None (mechanical transmission) |
| Management Emphasis | Vector control, resistant varieties | Hygiene, resistant varieties |
Integrated Pest Management (IPM) is crucial for both diseases. The National Food Security Mission (NFSM) promotes IPM practices in agriculture, including tomato cultivation. The scheme aims to increase production and productivity while minimizing environmental impact.
Conclusion
Leaf curl and mosaic diseases pose significant threats to tomato production, impacting yield and quality. Effective management relies on a combination of preventive measures like resistant varieties and cultural practices, alongside targeted interventions for vector control and hygiene. Integrated Pest Management strategies, incorporating biological control and resistant cultivars, are crucial for sustainable tomato farming. Continuous research and development of disease-resistant varieties remain vital for ensuring food security and farmer profitability.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.