The Diagnostic Lab conducts potato virus testing in support of the potato certification program. During the winter post-harvest test, potato virus Y (PVY) is tested in latent virus carrier varieties such as Russet Norkotah, Shepody, and Silverton. Also, during the summer virus test, PVX, PVY, and PVYn tests are offered for potatoes in order for growers to meet certification requirements. In the past, G-1 seed lots have been required to be PVYn tested. Latent virus carrier varieties such as Russet Norkotah, Shepody, and Silverton have been required to be PVY tested. The lab also provides potato virus testing for potato inspectors during the inspection season and also participates in national potato virus surveys. 

Testing
Virus testing in potato is conducted using an ELISA test, which detects the presence of a specific virus. The department currently conducts virus tests for potato virus A, potato virus M, potato virus S, potato virus X, potato virus Y, potato virus Y-necrotic, potato leaf roll virus, tomato spotted wilt virus, and potato latent virus. Typically, customers are required to submit samples of at least 410 leaflets for most virus tests. A 400 leaflet sample is then tested for PVY, PVX, and/or PVYn during the summer virus test and winter post harvest test. Samples are typically composited into 10 leaflets per test well for a total of 40 test wells per sample. Results are given as the number of positive test wells per total wells and as a percentage of the disease. Potato sprouts can also be tested for virus at an additional charge.