Leafroll virus causes which combination of symptoms in fall?

Leafroll virus causes which combination of symptoms in fall?

• A. Upward curling leaves
• B. Red and gold colors in fall with downward turning leaves
• C. Powdery coating
• D. Bud break delay

Answer: (B)

Leafroll virus manifests in fall with a distinctive combination: leaves that turn red or gold and curl downward along the veins. This happens because the virus disrupts the phloem and alters hormone balance, reducing chlorophyll and promoting pigment changes (anthocyanins and carotenoids) in autumn, while the tissue around the veins causes the leaf margins to roll downward. This set of symptoms is characteristic of leafroll, setting it apart from fungal powdery coatings or other issues that cause different leaf shapes or timing, such as bud break delays.

Leafroll virus manifests in fall with a distinctive combination: leaves that turn red or gold and curl downward along the veins. This happens because the virus disrupts the phloem and alters hormone balance, reducing chlorophyll and promoting pigment changes (anthocyanins and carotenoids) in autumn, while the tissue around the veins causes the leaf margins to roll downward. This set of symptoms is characteristic of leafroll, setting it apart from fungal powdery coatings or other issues that cause different leaf shapes or timing, such as bud break delays.