Dioscorea mosaic virus

Potyvirus nippodioscoreae is a viral plant pathogen belonging to the genus Potyvirus. It is specifically known for infecting plants of the genus Dioscorea, commonly referred to as yams. As a systemic disease, it impacts the entire vascular system of the host plant, often persisting in tubers throughout the dormant period.

The host range of this virus is primarily restricted to yam species used for food production and medicinal purposes. Since yams are vegetatively propagated, the virus poses a significant risk to the longevity and productivity of crops, as infected tubers serve as the primary source of inoculum for subsequent growing seasons.

Symptoms of the infection typically appear as a mosaic pattern on the leaves, characterized by irregular patches of light and dark green coloration. Other notable signs include leaf distortion, chlorosis, stunting of the plant's overall growth, and reduced tuber size. These symptoms are often more pronounced under suboptimal environmental conditions.

Transmission occurs through two main routes: the use of infected planting material and the feeding activity of aphid vectors. Aphids acquire the virus from infected tissues and transmit it to healthy plants within seconds. This non-persistent mode of transmission makes the management of vector populations a challenging yet essential task for agronomists.

Management strategies focus on strict sanitation and the use of certified, virus-free planting material. Growers are advised to implement regular roguing of symptomatic plants, maintain effective weed control to eliminate alternative hosts, and apply insecticides to manage aphid populations when pressure is high to prevent the secondary spread of the virus.