Controlling Yellow Mosaic Virus in Mung Bean (Moong)

Identifying Yellow Mosaic Virus Symptoms

Early detection is crucial for managing YMV. Look for these signs in your moong crop:

• Yellow Patches: The most characteristic symptom is the appearance of bright yellow, irregular patches or spots on the leaves, often starting from the veins. These patches gradually enlarge and may cover the entire leaf.
• Stunted Growth: Infected plants often show stunted growth, producing fewer pods and seeds.
• Pod Malformation: Pods may be smaller, discoloured, and contain shrivelled seeds.
• Reduced Yield: Severely infected plants produce very little or no yield.

Symptoms are usually visible 15-20 days after sowing, especially on younger leaves.

Choosing Resistant Varieties

The most effective and economical way to manage YMV is by planting resistant or tolerant mung bean varieties. Always consult your local agricultural university or extension worker for recommended varieties suitable for your region. Some commonly known resistant varieties in India include:

• Pusa Vishal
• SML 668
• IPM 02-03 (Sikha)
• MH 421
• Samrat (IPM 205-7)

Using certified seeds of these varieties significantly reduces the risk of YMV infection.

Managing Whitefly Populations

Since whiteflies transmit the virus, controlling their population is vital. An integrated approach combining cultural and chemical methods works best.

Cultural Methods:

• Timely Sowing: Adjust your sowing time to avoid the peak whitefly population periods. For Kharif moong, early sowing in late June to early July can help escape severe whitefly infestation.
• Weed Management: Many weeds act as alternate hosts for whiteflies and the virus. Keep your fields and surrounding areas free of weeds.
• Yellow Sticky Traps: Install yellow sticky traps (10-12 traps per acre) in your field to monitor and trap adult whiteflies.
• Crop Rotation: Rotate moong with non-host crops like maize or sorghum to break the whitefly life cycle and reduce disease inoculum.
• Rouging: Regularly inspect your field and immediately remove and destroy any plants showing YMV symptoms to prevent further spread.

Chemical Control:

Chemical insecticides should be used judiciously, especially when whitefly populations are high. Always follow the instructions on the product label for dosage and safety.

• Seed Treatment: Treat seeds with systemic insecticides like Imidacloprid (e.g., 5-7 g per kg of seed) or Thiamethoxam (e.g., 3 g per kg of seed) before sowing. This provides protection to young seedlings for the first 20-30 days.
• Foliar Sprays: If whitefly infestation is observed after germination, spray systemic insecticides. Examples include:
  • Acetamiprid 20% SP (e.g., 100-125 g per hectare)
  • Thiamethoxam 25% WG (e.g., 100 g per hectare)
  • Imidacloprid 17.8% SL (e.g., 125-150 ml per hectare)
  Spray during cooler parts of the day and ensure good coverage. Repeat sprays may be needed based on whitefly population and disease incidence.
• Neem Oil: For organic farming or as an initial measure, neem oil (e.g., 3-5 ml per litre of water) can deter whiteflies and disrupt their feeding and reproduction.

Integrated Management Strategy

The most successful approach to controlling Yellow Mosaic Virus in moong is to combine all available methods. Start with planting resistant varieties and treating seeds. Monitor your crop regularly for whiteflies and YMV symptoms. Implement timely cultural practices like weeding and rouging. Use insecticides only when necessary, based on pest thresholds, to protect beneficial insects and prevent resistance development.

By adopting an integrated pest and disease management strategy, farmers can significantly reduce the incidence of Yellow Mosaic Virus, protect their moong crop, and ensure a healthy and profitable harvest.