Controlling PVY in Seed: What Works and What Does Not

Potato Virus Y (PVY) has again emerged as one of the primary pests of potatoes in North America. While difficult to manage, the PVY complex has taken on a whole new level of importance with the recent emergence of the PVYN and PVYN:O strains along with the PVYO strains. Additionally, several cultivars have been released and are widely grown which express symptoms to PVY in a latent manner and show increased transmission of the virus into seed stocks. Certification schemes have long been utilized to control virus diseases. Under the current situation, however, programs have been struggling to get a handle on this problem. Specific strategies to manage this disease include the use of strict disease tolerances, roguing of infected plants, production practices such as field and/or lot isolation, manipulation of planting and killing dates, timely insecticide applications and border cropping, as well as, cultivar resistance. Use of limited generation greenhouse material has demonstrated minimal effectiveness in keeping PVY infections low within 1 to 2 years of initial field growth. Roguing has not been effective in reducing the population of PVY infected plants in latent cultivars such as Russet Norkotah. Aphid control has been largely ineffective in stopping late season infections. Planting and killing date manipulation has demonstrated some effect in controlling spread as have isolation of seed lots from infected stocks and growth of resistant cultivars. Utilizing strict tolerances has not been effective in controlling spread of PVY, especially for re-certification, but has allowed growers to maintain reasonable levels of PVY in seed stocks utilized for commercial production.