Potato (Solanum tuberosum L.) is a plant of Solanaceae family, its underground tubers are edible and it is one of the main food crops in the world. Propagation of potato is mainly asexual by seed potato. In Taiwan, seed potatoes are either mainly imported, or from breeding centers and supply system, or by potato farmers. However, the potato seeds could be highly variable, and pathogens are easily transmitted through seed potato to healthy plants, resulting in multi-infections of virus diseases, and in turn causing big loss in potato production. Therefore, the quality of seed potato is crucial to the quality and yield of consumable potato.

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Virus transmission can not only trough seed potato, but also mechanical contact, e.g. tools and insect bites. The common symptoms of infection mainly appear on leaves, usually mosaic symptoms. The leaves are yellow-green uneven phenomenon, and occasionally gangrenous streaks or water dipping spots, the surface of the affected leaves is uneven, shrunken or deformed, the color of the new leaves becomes pale yellow, the plants are dwarfed, and the stems are dwarfed or clustered. The main types of potato viruses are Potato virus Y (PVY), Potato virus S (PVS), Potato virus X (PVX), Potato leaf roll virus (PLRV). The detection method in lab adopts ELISA detection and RT-PCR detection.

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Potato virus S (PVS), most of the potato plants infected with PVS do not show obvious symptoms. The initial symptoms of the disease are darkening of the leaf veins or wrinkled leaves, resulting in poor plant growth. Some virus strains can cause mottled or browning in some cultivars. In severe cases, upper leaves will produce gangrenous spots, and lower leaves will not turn yellow to produce green spots. PVS can persist in potato tubers and infect other plants due to mechanical contamination of sap.

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Lateral flow rapid test can reach a similar sensitivity and specificity to ELISA, but surpasses ELISA in the simplicity of operation and saving of time on virus detection. Considering of its advantages of no need for equipment and low cost, making rapid test suitable for on-site and real-time virus testing and monitor in potato farms, and thus being a good tool for potato farmers and quarantine agencies to do virus control. Agitest Potato Virus S Rapid Test Strip is able to detect trace amount of PVS in potato leaves within 15 minutes. No equipment is required for conducting the test, and results can be interpreted visually. Strips can be stored and transported at room temperature environment.