Potato leafroll virus

Potato leafroll virus (PLRV) is a significant plant pathogen belonging to the genus Polerovirus. It is a phloem-limited virus that severely disrupts the translocation of assimilates from leaves to the tubers, causing profound physiological stress to the plant.

The primary hosts for this virus are members of the Solanaceae family, including potatoes, tomatoes, and peppers, though it can also persist in various weed species that serve as overwintering reservoirs.

Symptoms are distinct: leaves exhibit upward rolling along the midrib, often becoming leathery and chlorotic. In affected tubers, particularly in sensitive varieties, internal vascular necrosis (often called net necrosis) occurs, which makes the harvest commercially unacceptable.

The virus is transmitted by aphids, most notably the green peach aphid (Myzus persicae), in a persistent, circulative manner. Once an aphid acquires the virus, it remains a vector for the remainder of its lifespan, facilitating rapid spread across large areas during warm, dry growing seasons.

Damage caused by PLRV can lead to significant yield reductions, sometimes exceeding 70% in untreated crops. Control relies on an integrated pest management approach: planting certified virus-free seed tubers, maintaining spatial isolation from older potato fields, managing weed hosts, and employing systematic aphid control programs during the critical early stages of crop emergence.