Cucurbit aphid-borne yellows virus

The Cucurbit aphid-borne yellows virus (CABYV), a member of the genus Polerovirus, is a major viral pathogen affecting various cucurbitaceous crops worldwide. It is primarily known for causing systemic infections in cucumber, melon, zucchini, and pumpkin, leading to severe yield reductions in both field and greenhouse environments.

The virus is characterized by its persistent, circulative mode of transmission. It is not transmitted mechanically or through seeds, but rather exclusively by aphid vectors, most notably the cotton aphid (Aphis gossypii) and the green peach aphid (Myzus persicae). Once an aphid acquires the virus from an infected host, it remains a vector for the rest of its lifespan.

Symptoms of CABYV infection typically appear as a distinctive interveinal yellowing (chlorosis) of the older and middle leaves, while the veins remain green for an extended period. As the disease progresses, the leaves become thickened, brittle, and leathery. Affected plants often exhibit reduced fruit set and stunted growth, which severely impacts the marketability of the produce.

Disease development is heavily influenced by the presence of aphid populations and reservoir hosts. The virus survives between seasons in weed species or volunteer cucurbits. In regions with warm climates, the overlapping of crop seasons facilitates a continuous presence of aphids, which significantly increases the risk of early-season infections.

Management of CABYV requires an integrated approach focusing on minimizing aphid activity and reservoir sources:

• Strict weed control in and around production areas to eliminate viral reservoirs.
• Utilization of physical barriers like insect-proof netting in greenhouses.
• Implementing systemic insecticide programs to control aphid populations.
• Adhering to strict crop rotation and spatial isolation from older, potentially infected crops.