Risk and spread of plant viruses.

Risk and spread of plant viruses. Plant viruses can cause many diseases in our crops. The effects of viruses can range from discolorations and deformities – which make products less valuable or worthless – to loss of the plant. But virus infection can also be symptom-free; in that case the host plant appears to be healthy. However, undetected infections can have serious consequences for the export of agricultural products, especially if the virus concerned has a quarantine status in other countries. Standard plant protection agents do not work against plant viruses; once plants are infected by a virus they can no longer be cured. Farmers and growers therefore do everything they can to keep their crops virus-free. They begin the crop with certified virus-free material (seeds, cuttings or other planting material). In addition, they take measures to minimise virus transmission to their crop and within their crop. To do this effectively, it is important to understand how viruses spread and move from one plant to another.see