Potato-infecting viruses cause significant damage worldwide and represent a significant threat to seed potato industries. The incidence of virus in seed potatoes can have a significant impact on crop quality (both seed and ware). Virus can result in seed crops not meeting the official standard for a class (downgrading) or even for certification as seed potato (failed). The presence of virus in seed potato crops may also enable damaging spread of virus during the growing year. There are about 40 viruses infecting cultivated potatoes, some of them like Potato Leaf Roll Virus (PLRV) and Potato Viruses Y, A, V, S, M and X are distributed worldwide in potato-growing areas.
Virus testing is carried out mainly in support of the Scottish Seed Potato Classification Scheme. In addition a service is provided in support of the wider seed potato industry in Scotland. Tests are carried out for the following viruses:
- Potato Viruses Y, X, A, S, M, V,
- Potato Leaf Roll Virus
- Tomato Black Ring Virus
- Potato Mop Top Virus; and
- Tobacco Rattle Virus.
- Tests on samples submitted by Scottish Government Agriculture and Rural Delivery Division inspectors during the course of growing crop inspections
- Postharvest tuber testing of stocks in which growers have failed to control aphids during the growing season
- Regular surveys of selected stocks for quality control purposes to ensure that virus levels are well within EU marketing tolerances for basic seed
- Postharvest tuber tests on samples destined for export to ensure that they conform to the requirements of importing countries
- Diagnosis of virus symptoms in samples submitted growers and agricultural advisors.
The following test methods are employed:
- ELISA (Enzyme linked immunosorbent assay)
- Real-time PCR (Polymerase Chain reaction)
Research and development is carried out on improvement of test methods, and the epidemiology of virus diseases of potato: