Virus
/ˈvaɪrəs/
Definition
Virus, in plant biology, refers to an infectious agent made of genetic material enclosed in a protein coat that can reproduce only inside living cells. In plants, it enters through wounds or insect feeding, then moves through tissues and disrupts normal growth. Unlike fungi or bacteria, it is not a cell and does not live independently. Plant virus infections often cause mottling, mosaic patterns, distortion, or stunting.
Effects on Plants
- Growth and yield damage: Infected plants may become stunted, produce fewer flowers or fruits, and lose vigor because normal cell activity and energy use are disrupted.
- Typical visible symptoms: Common signs include mosaic or mottled leaves, yellowing, ring spots, leaf distortion, and uneven growth, though symptoms can vary by host plant and strain.
- Spread through vectors and tools: Many cases move between plants by sap-feeding insects such as aphids and whiteflies, and some can spread through contaminated hands, tools, cuttings, or grafting.
- Long-term persistence: Once inside a plant, it usually cannot be cured with sprays. Management focuses on removing affected material, starting with clean stock, and reducing sources of spread.