DEVELOPMENT OF SUSTAINABLE SYSTEM-BASED MANAGEMENT STRATEGIES FOR TWO VECTOR-BORNE, TUBER NECROTIC VIRUSES IN POTATO

Necrotic potato viruses are the most important plant disease threat for the U.S. Potato Industry. Potato virus Y (PVY) is the number one cause of seed potato rejection in North America, it is transmitted non-persistently by aphids. Potato mop-top virus (PMTV), which is transmitted by the soil-borne pathogenic protist Spongospora subterranea, has spread to at least six seed potato producing states, and currently is present in 5% of seed potatoes from Maine. Since S. subterranea is common in peat-based potting mix, which is used to produce early generation seed potatoes, this pathogen has become widespread in North America. Current seed potato certification protocols are ineffective at managing these diseases, while pesticides are ineffective for managing both viruses and vectors listed above. We have made substantial progress in helping the industry manage these pathogens, but further work is needed (see progress report). Critical stakeholder needs are virus-resistant potato varieties, inexpensive high throughput testing of tubers for pathogens prior to planting, field management methods to reduce vector populations and pressure, social science information to aid in effectively implementing new technologies, and extension to teach farmers about these new management and testing methods.The potato industry views necrotic potato viruses as the primary threat to potato production in the United States. The long term goal of this project is to provide farmers with improved management strategies, and economic analysis tools to guide them in implementation of necrotic virus management strategies in order to reduce losses to necrotic viruses. The two necrotic viruses in this project, PVY and PMTV, infect other major crops and ornamental plants and are the type members of their genera, so knowledge gained through this work will improve general knowledge of plant virology as well as production of numerous specialty crops in the United States and throughout the world. PMTV is spread by the broad host range S. subterranea, which is also a pathogen, and which causes powdery scab on potato tubers and root galls on roots of many plant species.Therefore, our specific long term project goals are to:To translate high throughput detection of PVY and PMTV in dormant potato tubers, their vectors, and, for PMTV, in soil and potting mix, to plant diagnostic labs.To improve virus-vector management through development of epidemiological models and through research-based recommendations for potato production.To develop molecular markers for resistance genes against PVY and PMTV, and Ss; to clone at least one PVY resistance gene; and to understand virus impacts on the physiology of stored potatoes.To identify economic, or incentive barriers to effective disease management and to use this information to aid in industry adoption of improved management strategies and harmonized regulations.Outreach will occur at regional and national farmer education meetings, demonstration field plots, online via a project website hosted by Potatoes USA, and through online extension publications and videos. The majority of our project co-PDs and co-PIs are regular speakers at industry meetings and they will continue to provide outreach of knowledge generated by this project.