UPSC MainsAGRICULTURE-PAPER-II201115 Marks150 Words
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Q30.

NETO and NEPO viruses.

How to Approach

This question requires a concise explanation of NETO and NEPO viruses, their impact on horticulture, and their distinguishing features. The approach will be to first define each virus, then discuss their host range and symptoms. A comparative table highlighting differences is crucial. Finally, mention the control measures and their significance in maintaining horticultural productivity. The answer should be structured to demonstrate a clear understanding of the topic within the word limit.

Model Answer

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Introduction

Plant viruses pose a significant threat to horticultural crops globally, causing substantial economic losses. NETO (New Delhi Virus) and NEPO (Nepal Enation Potyvirus) are two such viruses belonging to the Potyvirus genus, commonly affecting solanaceous crops like tomatoes, potatoes, and eggplants. NETO, first identified in India in 2013, has rapidly spread, while NEPO is a more established virus in the region, known for causing enation symptoms. Understanding their differences and impact is crucial for effective disease management in horticulture.

NETO Virus (New Delhi Virus)

NETO is a novel Potyvirus discovered in tomato plants exhibiting severe yellow mottle symptoms in New Delhi, India. It is closely related to other Potyviruses but possesses unique genetic characteristics. It's a single-stranded RNA virus transmitted by aphids (primarily *Myzus persicae*).

  • Host Range: Primarily affects tomato, but can also infect pepper and eggplant.
  • Symptoms: Severe yellow mottle, leaf distortion, stunting, and reduced fruit yield. In severe cases, plants can die.
  • Impact: Rapid spread and high virulence have made NETO a significant threat to tomato production in India and other parts of Asia.

NEPO Virus (Nepal Enation Potyvirus)

NEPO is a widespread Potyvirus affecting a wide range of crops, particularly solanaceous plants. It is also transmitted by aphids.

  • Host Range: Affects tomato, potato, eggplant, pepper, and some cucurbits.
  • Symptoms: Enations (leafy outgrowths), chlorosis (yellowing), stunting, and reduced fruit quality. Symptoms are often less severe than those caused by NETO.
  • Impact: Reduces yield and quality, impacting farmer income and marketability of produce.

Comparative Analysis

Here's a table summarizing the key differences between NETO and NEPO viruses:

Feature NETO Virus NEPO Virus
Discovery 2013, New Delhi, India Earlier, widespread in Asia
Virulence Higher, causing severe symptoms Lower, symptoms often milder
Host Range Primarily tomato, pepper, eggplant Tomato, potato, eggplant, pepper, cucurbits
Genetic Differences Unique genetic markers differentiating it from other Potyviruses Shares genetic similarity with other Potyviruses
Spread Rapid and aggressive More established, slower spread

Control Measures

Effective management strategies are crucial for both viruses.

  • Vector Control: Aphid control through insecticides and biological control agents (e.g., parasitoids, predators).
  • Resistant Varieties: Developing and deploying resistant or tolerant cultivars.
  • Hygiene Practices: Using disease-free planting material and implementing strict sanitation measures in nurseries and fields.
  • Crop Rotation: Rotating crops to break the disease cycle.
  • Monitoring: Regular monitoring of crops for symptoms and early detection of outbreaks.

The Indian government’s National Programme for Plant Protection and Management (NPPPM) promotes integrated pest and disease management practices, which are relevant for controlling these viruses. The scheme focuses on surveillance, diagnostics, and farmer awareness.

Conclusion

NETO and NEPO viruses pose distinct threats to horticultural crops, particularly solanaceous plants. While NEPO is a well-established virus, NETO’s recent emergence and higher virulence necessitate intensified surveillance and management strategies. Integrated approaches focusing on vector control, resistant varieties, and strict hygiene are vital for safeguarding horticultural productivity and ensuring food security. Continuous research and development of diagnostic tools and resistant cultivars remain crucial for long-term sustainable management.

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.

Additional Resources

Key Definitions

Enation
Enations are leafy, tumor-like outgrowths on stems and leaves, often caused by plant viruses like NEPO.
Potyvirus
Potyviruses are a large genus of plant viruses belonging to the family Potyviridae. They are characterized by their flexuous, filamentous particles and are transmitted by aphids.

Key Statistics

NETO virus has been reported to cause yield losses of up to 80% in tomato crops in affected regions (Source: ICAR-IIHR, 2019 - Knowledge cutoff).

Source: ICAR-IIHR

Aphids can transmit plant viruses like NETO and NEPO over considerable distances, contributing to rapid disease spread.

Source: FAO - Knowledge cutoff

Examples

Impact on Farmer Livelihoods

The prevalence of NETO and NEPO viruses has led to reduced tomato yields and quality, impacting farmer income and forcing some to abandon tomato cultivation altogether.

Frequently Asked Questions

Can NETO and NEPO viruses infect the same plant simultaneously?

Yes, co-infection with NETO and NEPO viruses can occur, potentially leading to more severe symptoms and complex disease management challenges.

Topics Covered

Plant PathologyVirologyHorticulturePlant VirusesDisease ManagementPlant Protection