Pepper vein yellows virus

Pathogen and Disease Type: Pepper vein yellows virus (Polerovirus pevyv) is a member of the Polerovirus genus within the Solemoviridae family. It is a phloem-restricted virus, meaning it colonizes the plant's vascular tissue. It is not transmissible through mechanical sap inoculation or seed transmission, focusing its infection pathway exclusively on insect vectors.

Affected Crops: The virus primarily impacts solanaceous crops, with significant economic damage reported in peppers, tomatoes, and potatoes. Its host range also extends to various weed species and several other vegetable crops, which may serve as silent reservoirs for the pathogen in field environments.

Symptoms and Signs: The most characteristic symptom is the striking interveinal chlorosis (yellowing) of leaves, particularly affecting older foliage first. Infected plants exhibit stunted growth, reduced leaf size, and increased leaf brittleness. The yellowing pattern often creates a contrast with green veins, leading to a decline in photosynthetic efficiency.

Development and Spread: Transmission occurs via an aphid vector, most notably Myzus persicae (green peach aphid), in a persistent, circulative manner. Once an aphid acquires the virus from an infected plant after a period of feeding, it remains infectious for the remainder of its life, allowing for widespread dispersion throughout a field.

Harmfulness and Protection: The virus causes severe yield losses by impeding the translocation of carbohydrates, leading to poor fruit development. Management relies on:

• Integrated Pest Management (IPM) to control aphid populations using targeted insecticides.
• Deployment of resistant or tolerant crop varieties.
• Sanitation, including the removal of infected plants and surrounding weed hosts.
• Use of floating row covers or physical barriers to exclude vectors in early growth stages.