Potato leaf roll virus

Potato leaf roll virus (PLRV) is a major viral pathogen of potatoes, classified within the Polerovirus genus. This disease primarily affects the phloem tissues of the plant, causing a disruption in the translocation of sugars from the leaves to the tubers, which severely stunts plant growth and reduces overall yield quality.

While the potato is the most economically significant host, PLRV also affects other Solanaceae species, including tomatoes, peppers, and various nightshade weeds. These weed reservoirs are crucial in the disease cycle, as they harbor the virus during intervals between potato growing seasons.

The primary symptom is the upward rolling of the leaflets of the upper leaves, which often become leathery and brittle. In some cultivars, these leaves develop a yellowish or purplish discoloration. Plants infected early in the season appear stunted, while plants infected during the growing season may show symptoms primarily on the younger leaves near the top.

The virus is transmitted by several aphid species, most notably the green peach aphid (Myzus persicae), in a persistent, circulative manner. Once an aphid acquires the virus from an infected plant, it remains a vector for the rest of its lifespan. Furthermore, the virus is tuber-borne, meaning that if infected seed tubers are planted, the resulting daughter plants will inevitably carry the infection.

Effective management focuses on a multi-faceted approach, emphasizing the use of certified virus-free seed potatoes. Preventive measures include regular monitoring and control of aphid populations using systemic insecticides, removing volunteer potato plants, and practicing strict weed control. Timely destruction of haulms at the end of the season is also essential to prevent late-season aphid transmission to the tubers.