Nepovirus

Nepovirus is a genus of plant-pathogenic viruses that belong to the family Secoviridae. The name is derived from the term "nematode-transmitted polyhedral viruses." These pathogens are highly stable and are known to cause significant economic losses in various horticultural and agricultural crops worldwide, as they can persist in plant tissues for the lifetime of the host.

These viruses affect a wide array of host plants, including woody perennials like grapevines and fruit trees, as well as soft fruits like raspberries and strawberries. The infection typically results in systemic disease, where the virus colonizes the plant's vascular system, leading to physiological disruption and reduced vitality of the infected crops.

Symptomatology is diverse and often manifests as distinct foliar patterns. Common signs of infection include

• chlorotic rings and line patterns;
• mosaic-like mottling;
• leaf distortion and stunted growth;
• reduced yield and poor quality of fruits;
• decline in plant vigor.

The transmission of Nepoviruses is primarily mediated by soil-borne nematodes belonging to the genera Xiphinema, Longidorus, and Paralongidorus. These nematodes act as vectors, acquiring the virus by feeding on the roots of infected plants and subsequently transmitting it to healthy ones. Additionally, human activities such as the distribution of infected propagative material (cuttings, grafts, or seeds) play a major role in long-distance viral dissemination.

Control measures must focus heavily on prophylaxis since there are no chemical agents available to cure an infected plant. Essential strategies include sourcing certified virus-free planting stock, managing soil nematode populations through crop rotation or solarization, and practicing strict sanitation in nurseries. Removing and destroying symptomatic plants is crucial to prevent further spread within the field or orchard.