Vector: Aphids

Viral Disease

Vector: Aphids

Viral Disease

Vector: Aphids

Viral Disease

Onion yellow dwarf virus (OYDV) is a significant viral disease affecting onions, garlic, shallots, and a few ornamental Allium species. The first sign of infection in young onion plants is the appearance of yellow streaks at the base of the first true leaves. As the disease progresses, these streaks spread, leading to complete yellowing of the leaves. Infected leaves often become crinkled, flattened, and may droop over, severely stunting bulb growth and reducing yield.

• Initial Symptoms:

  • Yellow streaks appear at the base of the first true leaves in young onion plants.

• Progression:

  • Yellow streaks spread, leading to complete yellowing of all developing leaves.
  • Leaves may become crinkled, flattened, and tend to droop over.
  • Bulb size is significantly reduced, affecting yield.

• Causal Agent:

  • OYDV is a potyvirus with a narrow host range, mainly affecting onions, garlic, shallots, and a few ornamental Allium species.

• Survival and Transmission:

  • Survives in infected bulbs and sets, facilitating spread during vegetative propagation.
  • Transmitted by aphids, especially the green peach aphid (Myzus persicae), in a nonpersistent manner.
  • Can persist in volunteer onions, which act as virus reservoirs.

• Seed Transmission:

  • OYDV is not seed-borne, but infected plants produce poor-quality seeds.

• Management:

  • Control of aphid populations is essential to reduce the spread of the virus.
  • Use of virus-free bulbs and sets.
  • Removal of volunteer onions from fields to prevent disease persistence.