Duration: 10/01/2026 to 09/30/2031

Administrative Advisor(s):

NIFA Reps:

Non-Technical Summary

Potato is propagated vegetatively using seed tubers. To minimize disease incidence in seed tubers and reduce varietal mixtures, a complex seed potato certification system has been established in the U.S., thus protecting the potato industry. Viruses, such as potato virus Y, and virus-like pathogens, are major pathogens that can be transmitted via infected seed tubers and result in yield and quality losses as well as pose a persistent problem for profitable seed production. The goal of the WERA89 group is to promote concerted efforts among potato researchers to work collaboratively and develop sustainable management strategies for potato growers and stakeholders so that they can effectively mitigate negative impacts of established and emerging viruses and virus-like pathogens.

Statement of Issues and Justification

Viruses and virus-like pathogens of potato are costly to control, requiring limited generation seed programs and the targeted control of virus vectors, like insects and nematodes, with pesticides and other methods to reduce their spread and minimize their impact. Potato diseases caused by viruses result in hundreds of seed acres and/or their tuber products being rejected from seed certification and also result in commercial losses due to reductions in yield and quality leading to huge financial losses to the producer. Some of the more prevalent viruses of potato include alfalfa mosaic virus (AMV), potato mop-top virus (PMTV), tobacco rattle virus (TRV), tomato spotted wilt virus (TSWV), potato leaf roll virus (PLRV), potato virus M (PVM), potato virus S (PVS), potato virus X (PVX) and, most importantly, potato virus Y (PVY) and its various strains. Additionally, the causal agents of purple top disease and zebra chip, which are not viruses but are epidemiologically similar to viruses, have recently become established in the western potato production areas.

Release of new cultivars highly susceptible to PVY, but asymptomatic when infected, has dramatically increased issues with PVY throughout the western potato growing regions. PVY is of particular concern because insecticides have not been effective for reducing PVY spread. Other management options, such as removal of symptomatic plants, are not practical for managing this virus at a large scale. Additionally, multiple strains of PVY have been found to occur throughout the western growing region creating difficulties for disease diagnosis and further exacerbating the efforts to reduce the impact of PVY. Of major concern, is the fact that new strains are supplanting the common strain of PVY (PVY^O) resulting in milder symptoms on the plants, greater spread throughout the crop, and potentially significant tuber necrosis injury. Some of the newer cultivars which are resistant to the common strain of PVY have been found to be very susceptible to some of the newer strains.

Established and emerging virus strains pose a constant threat to certified seed and commercial potato production. In the last decade, PVA and PVM were not known to occur in the West. PVM seems to have been contained by continued efforts of certification programs, while PVA has become endemic in some regions and absent in others. New strains of PVY, particularly those that produce internal tuber necrosis and reduced yield, were not known in the US prior to the late 1990s but are now commonly found and have become more prevalent in most production areas. Since then, PVY strains have been identified and monitored in the potato-growing regions of the US, and efforts to quantify their impact on the crop and evaluate the performance of new cultivars currently being released from the potato breeding programs have been initiated and are in progress. In the past, TSWV has been a sporadic problem in the western region but is currently becoming a significant problem in areas where it has become endemic. Finally, soil borne viruses such as potato mop-top virus (PMTV), which is vectored by Spongospora subterranea f. sp. subterranea, and tobacco rattle virus (TRV), spread by the stubby root nematode, are serious issues in many western production regions with increasing economic losses due to tuber necrosis and downgrading of raw potatoes. As soil borne viruses increase in prevalence, they are likely to become one of the most significant limitations to potato production that producers will be facing in the near future. Emerging virus threats are always on the horizon and pose a wider risk to the potato industry as a whole because many more new cultivars are being developed with little information on their reaction to all viruses as well as the industry moving more seed each year from more diverse areas to answer production needs.

There are public and environmental concerns surrounding the use of pesticides on potatoes. Potato growers are faced with the potential loss of key pesticides because of cancellation of registration. In addition, difficulties in developing new information for re-registration or development of new pesticides are becoming more difficult each year. Lastly, pest resistance to current pesticides is always of concern. Pesticides targeting the vectors of some viruses and virus-like pathogens have been useful in the management of diseases like potato leaf roll and zebra chip. Certainly, the loss of pesticides or loss of effectiveness will reduce yield and increase quality losses if alternative solutions for vector management are not developed.

Related, Current and Previous Work

WERA89 is unique in that fosters a collaborative platform for both seed potato certification agencies and potato researchers to discuss topics related to seed potato certification challenges; pest and pathogen management strategies; potato breeding innovations and benefits; and education on current diagnostic capabilities and challenges.

For 2021-2025, a highly collaborative multi-state and multi-institutional project focusing on necrotic viruses was funded by the USDA-NIFA-SCRI program. This project focused on the translation of virus detection methods to plant diagnostic labs, developed research-based recommendations for improving virus-vector management, developed molecular markers for resistance genes against PVY and PMTV, and identified economic barrier to adoption of improved virus management practices. There has been progress towards the development of virus resistance potato germplasm as well as understanding of the evolution of tuber necrotic strains of PVY. A new immunocapture duplex RT-qPCR was developed to detect PMTV from dormant tubers. Of note, there also has been an impetus for direct tuber testing validation research for PVY across seed potato certification agencies in Montana, Michigan, North Dakota, Colorado, Idaho, and Wisconsin.

In previous years, major efforts were funded by the USDA-SCRI program focused on PVY in 2009-2014 and again from 2015-2019. These efforts resulted in the development of PVY strain typing tools, refinement of methods for PVY detection in tubers (both serological and molecular), new potato cultivars displaying resistance to recombinant PVY strains, and enhanced management of PVY vectors. Since 2013-14, the Northwestern Potato Research Consortium supported the creation of a team of researchers in the PNW. This team includes most of the researchers involved in virus management projects in three states, ID, WA, and OR; it is now expanded to address new, emerging virus problems. Additionally, from 2016 to the present, members of WERA89 successfully leveraged support through several small block grants through the Idaho and Washington departments of agriculture and partnered with researchers across the US in large successful USDA-SCRI grants focused on potato viruses and virus-like diseases.

The continued success since the inception of the WERA89 group highlights the value of a joint, comprehensive approach to address virus problems affecting potato. Members of this team will continue to cooperate on various types of federal grant proposals to be submitted to USDA, NSF, and other programs. The WERA89 group is vital for continued collaboration across multiple states that promotes judicious use of resources, identifies priorities, and coordinates research efforts to solve potato virus and virus-like disease problems.

Objectives

Procedures and Activities

Annual meeting. The WERA89 executive committee will arrange for an annual meeting site where participants can come together to discuss current concerns of virus and virus-like diseases occurring in potato crops. This forum will also include the presentation of on-going research on potato viruses and virus-like diseases, their vectors and alternative hosts. In addition, participants will have the opportunity to consider research priorities for the upcoming years.

Committee projects. Subgroups of the participants will be formed to work on specific projects throughout the year including educational materials, presentations, and reference sheets.

Expected Outcomes and Impacts

Projected Participation

View Appendix E: Participation

Educational Plan

In the short-term, we plan to extend our findings to the researchers/scientists participating in WERA89 as well as other scientific colleagues with interest in potato virus and virus-like diseases and associated management strategies. Participants in WERA89 regularly interact with these potato researchers throughout the year as part of the active potato research community in the U.S. Through these interactions, results will be disseminated to all U.S. potato researchers at meetings among breeding programs, through meetings of the Potato Association of America (http://potatoassociation.org/), American Phytopathological Society, and via peer reviewed publications.  

Through longer-term interactions with members of the potato production and processing industry, we will transfer information developed by WERA89 participants to the grower community with the goal of increasing the adoption of new farming technologies, cultivars, and disease management strategies.

Effective communication between researchers and producers/processors will lead to more relevant research outcomes and faster adoption of results by stakeholders. 

Various participants have active web presences through which publications and news can be disseminated. 

We also help plan and participate in major outreach events and field days such as, but not limited to, Washington/Oregon Potato Conference, WSU Potato Field Day, Hermiston Farm Fair, OSU HAREC Potato Field Day, Idaho Potato Conference, ID field day(s) and others.

Various WERA89 participants are highly integrated into the producer-led industry organizations and research-oriented outreach channels. Outcomes of the WERA89 meetings will be efficiently communicated to all who are interested in potato production.

Organization/Governance

The committee will utilize a three-officer system containing a Chair, Vice Chair, Secretary and general membership. Each year, a new Secretary shall be elected at the annual meeting. At the end of the annual meeting, the previous year’s Secretary will move into the Vice Chair position and the Vice Chair will move into the Chair position. There will be an effort made to spread the officer duties around the Western Region so that no one state, or area will have all of the officer functions at any given time. Annual meetings will be rotated around the Western Region and the three officers will handle arrangements for these meetings.

Literature Cited

The literature cited is meant to convey the broad scope of publications members of this group have attributed to discussions held at the annual meetings in the previous period. In many cases, the research conducted and shown in this listing was greatly aided by those involved in being able to discuss this work in advance of beginning the project, during its progress, and prior to final publication.

Publications

2025

Chikh-Ali, M., Daniel, J., Usman Aslam, H. M., Agindotan, B., and Charkowski, A., 2025. Development of a duplex immunocapture reverse-transcription quantitative PCR for large-scale detection of potato mop-top virus in dormant potato tubers. Plant Disease 109:1354-1358.

Satoh-Cruz, M., Rhodes, S., Kurzer, D., Dorman, E., and Willbur, J. F. 2025. Prevalence of the potato virus Y strain composition impacting Michigan seed potato production.  Plant Health Progress 26:70-75. https://doi.org/10.1094/PHP-06-24-0063-S

Swisher Grimm, K. D., Quick, R. A., Feldman, M. J., and Charlton, B. A. 2025. Development of a greenhouse screen for the identification of potato mop-top virus and Spongospora subterranea resistance in Solanum tuberosum. PhytoFrontiers 5:411-417. httpS://doi.org/10.1094/PHYTOFR-11-24-0127-R

 

2024

Dahan, J., Orellana, G. E., Wald, K. B., Wenninger, E. J., Cooper, W. R., and Karasev, A. V. 2024. Bactericera cockerelli Picorna-like virus and three new viruses found circulating in populations of potato/tomato psyllids (Bactericera cockerelli). Viruses 16:415. https://doi.org/10.3390/v16030415

Daniel, J., and Chikh-Ali, M, 2024. Dynamics of potato virus Y infection pressure and strain composition in the San Luis Valley, Colorado. Plant Disease 108:1146-1151.

Funke, C.N., Tran, L.T., and Karasev, A.V. 2024. Screening three potato cultivars for resistance to potato virus Y strains: broad and strain-specific sources of resistance. American Journal of Potato Research 101:132-141 https://doi.org/10.1007/s12230-024-09946-6.

Gelles, N.A., Olsen, N., Thornton, M. K., and Karasev, A. V. 2024. Methods to induce sprouting in dormancy potato tubers for direct tuber testing of potato virus Y. American Journal of Potato Research 101:312-321. https://doi.org/10.1007/s12230-024-09960-8

Kamal, H., Kotapati, K., Tanaka, K., and Pappu, H. R. 2024. Investigating the roles of coat protein and triple gene block proteins of Potato mop-top virus using a heterologous expression system. International Journal of Molecular Sciences 25:6990. https://doi.org/10.3390/ijms25136990

Kamal, H., Lynch-Holmes, V., Pappu, H. R., and Tanaka, K. 2024. Starch plays a key role in sporosorus formation by the powdery scab pathogen Spongospora subterranea. Phytopathology 114:568-579. https://doi.org/10.1094/PHYTO-07-23-0224-R

Manasseh, R., Sathuvalli, V., and Pappu, H. R. 2024. Transcriptional and functional predictors of potato virus Y-induced tuber necrosis in potato (Solanum tuberosum). Frontiers in Plant Science 15:1369846. https://doi.org/10.3389/fpls.2024.1369846

Rodriguez-Rodriguez, M., Chikh-Ali, M., Feng, X., and Karasev, A. V. 2024. Genome sequences of six recombinant variants of potato virus Y identified in North American potato cultivars grown in China. Microbiology Resource Announcements 12: e00512-23 https://doi.org/10.1128/MRA.00512-23

Wenninger, E. J. and Rashed, A. 2024. Biology, ecology, and management of the potato psyllid, Bactericera cockerelli (Hemiptera: Triozidae), and zebra chip disease in potato. Annual Review of Entomology 69: 139-157. https://doi.org/10.1146/annurev-ento-020123-014734

 

2023

Chikh-Ali, M. and Karasev, A. V. 2023. Chapter 11. Virus diseases of potato and their control. In: Potato Production Worldwide (Eds., Caliskan, M.E., Bakhsh, A., and Jabran, K.), Elsevier, Inc.: London, San Diego, Cambridge, Oxford; pp. 199-211.

Dahan, J., Pedroni, M.J., Thompson, B.D., Chikh-Ali, M., Dandurand, L.-M., Kuhl, J. C., and Karasev, A. V. 2023. First report of tomato chlorotic dwarf viroid infecting litchi tomato (Solanum sisymbriifolium). Plant Disease 107:2564. https://doi.org/10.1094/PDIS-03-23-0422-PDN  

Gnanasekaran, P., Zhai, Y., Kamal, H., Smertenko, A., and Pappu, H. R. 2023. A plant virus protein, NIa-pro promotes disease development via by modulating Indole-3-acetic acid amido synthetase. Frontiers in Plant Science. 14:1112821. https://doi.org/10.3389/fpls.2023.1112821

Goyer, A. J., Bvindi, C. N. 2023. Overexpression of VQ motif-containing gene does not affect infection rates of potato with potato virus Y. American Journal of Potato Research 100: 233-239. https://doi.org/10.1007/s12230-023-09913-7

Goraya, M., Yan, G., Whitworth, J., and Swisher Grimm, K. D. 2023 Advancing nematode identification on potato: An isothermal recombinase polymerase amplification assay for stubby root nematode, Paratrichodorus allius. American Journal of Potato Research 101:52-64. https://doi.org/10.1007/s12230-023-09940-4

 Manasseh, R., Berim, A., Kappagantu, M., Moyo, L., Gang, D. R., and Pappu, H. R. 2023. Pathogen-triggered metabolic adjustments to potato virus Y infection in potato. Frontiers in plant science, 13:1031629. https://doi.org/10.3389/fpls.2022.1031629

 

 

2022

Dahan, J., Cooper, W. R., Munyaneza, J., and Karasev, A. V. 2022. A new Bactericera cockerelli picorna-like virus identified in populations of potato psyllids. Archives of Virology 167:177-182. https://doi.org/10.1007/s00705-021-05281-x

Ding, P., Chen, D., Feng, H., Li, J., Cao, H., Muning, T., Li, J., Hao, X., Han, P., Karasev, A.V., and Feng, X. 2022. Prevalence and strain composition of potato virus Y circulating in potato fields in China’s north-central province of Shanxi. Plant Disease 106:1434-1445 https://doi.org/10.1094/PDIS-09-21-1950-RE.

 Duellman, K. M.*, Whitworth, J., Lent, M. A., Bertram, M. C., and Randall, J. C. 2022. Mechanical transmission of Potato virus Y by seed cutting is not a contributing factor to increased virus in field production. Plant Health Progress 23:381-387. https://doi.org/10.1094/PHP-02-22-0011-RS 

  Kud, J., Dahan, J., Orellana, G. E., Dandurand, L.-M., and Karasev, A. V. 2022. A novel rhabdovirus associated with the Idaho population of potato cyst nematode Globodera pallida. Viruses 14:2718. https://doi.org/10.3390/v14122718

Mondal, S., Wintermantel, W. M., and Gray, S. 2022. Infection dynamics of potato virus Y isolate combinations in three potato cultivars. Plant Disease 107:157-166. https://doi.org/10.1094/PDIS-09-21-1980-RE

Mora, V., Ramasamy, M., Damaj, M. B., Irigoyen, S., Ancona, V., Avila, C. A., Vales, M. I., Ibanez, F., and Mandadi, K. K. 2022. Identification and characterization of new sources of zebra chip disease resistance among wild Solanum species. Frontiers in Microbiology 13:857493. https://doi.org/10.3389/fmicb.2022.857493

Ross, B. T., Zidack, N., McDonald, R., and Flenniken, M. L. 2022. Transcriptome and Small RNA profiling of potato virus Y infected potato cultivars, including systemically infected Russet Burbank. Viruses. 14:523. https://doi.org/10.3390/v14030523

Tran, L.T., Green, K. J., Rodriguez-Rodriguez, M., Orellana, G. E., Funke, C. N., Nikolaeva, O. V., Quintero-Ferrer, A., Chikh-Ali, M., Woodell, L., Olsen, N., and Karasev, A. V. 2022. Prevalence of recombinant strains of potato virus Y in seed potato planted in Idaho and Washington states between 2011 and 2021. Plant Disease 106:810-817. (https://doi.org/10.1094/PDIS-08-21-1852-SR).

Vales, M.I., Scheuring, D. C., Koym, J. W., Holm, D. G., Essah, S. Y. C., Wilson, R. G., Sidhu, J. K., Novy, R. G., Whitworth, J. L., Stark, J. C., Spear, R. R., Sathuvalli, V., Shock, C. C., Charlton, B. A., Yilma, S., Knowles, N. R., Pavek, M. J., Brown, C. R., Navarre, D. A., Feldman, M., Long, C. M., and Miller Jr., J. C. 2022. Vanguard russet: A fresh market potato cultivar with medium-early maturity and long dormancy. American Journal of Potato Research. 99:258–267.

Hoopes, G., Meng, X., Hamilton, J. P., Achakkagari, S. R., Freitas Guesdes, F. de A., Bolger, M. E., Coombs, J. J., Esselink, D., Kaiser, N. R., Kodde, L., Kyriakidou, M., Lavrijssen, B., van Lieshout, N., Shereda, R., Tuttle, H. K., Vaillancourt, B., Wood, J. C., de Boer, J. M., Bourke, P. M., Douches, D., van Eck, H. J., Ellis, D., Feldman, M. J., Gardner, K. M., Hopman, J. C. P., Jiang, J., de Jong, W. S., Kuhl, J. C., Novy, R. G., Oome, S.,  Sathuvalli, V., Tan, E. H., Ursem, R. A., Vales, M. I., Vining, K., Visser, R. G. F.,  Vossen, J., Yencho, G. C., Anglin, N. L., Bachem, C. W. B., Endelman, J. B., Shannon, L. M., Strömvik, M., Tai, H. H., Usadel, B., Buell, C. R., and Finkers, R. 2022. Phased, chromosome-scale genome assemblies of tetraploid potato reveals a complex genome, transcriptome, and proteome landscape that underpin phenotypic diversity. Molecular Plant 15:520-536.

 

2021

Combest, M. M., Moroz, N., Rogan, C., Tanaka, K., Anderson, J., Rakotondrafara, A.M., and Goyer, A. 2021. StPIP1, a predicted PAMP-induced peptide in potato, elicits plant defenses and is associated with disease symptom severity in a compatible interaction with potato virus Y. Journal of Experimental Botany 72:4472-4488.

Dahan, J., Wenninger, E. J., Thornton, M., Reyes-Corral, C. A., Olsen, N., and Karasev, A. V. 2021. Haplotyping the potato psyllid (Hemiptera: Triozidae), and the associated pathogenic bacterium ‘Candidatus Liberibacter solanacearum’ in non-crop alternative hosts in Southern Idaho. Environmental Entomology 50:382–389. https://doi.org/10.1093/ee/nvaa179

Elison, G. L., Novy, R. G. and Whitworth, J. L. 2021. Russet potato breeding clones with extreme resistance to potato virus Y conferred by Ry_chc as well as resistance to late blight and cold-induced sweetening. American Journal of Potato Research 98:411-419. https://doi.org/10.1007/s12230-021-09852-1

Mondal, S., Ghanim, M., Roberts, A., and Gray, S. M. 2021. Different potato virus Y strains frequently co- localize in single epidermal leaf cells and in the aphid stylet. Journal of General Virology 102:001576. https://doi.org/10.1099/jgv.0.001576

Novy, R.G., Whitworth, J. L., Stark, J. C., Spear, R. R., Schneider, B. L., Pavek, M. J., Knowles, N. R., Knowles, L. O., Charlton, B. A., Sathuvalli, V., Yilma, S., Brown, C. R., Brandt, T. L., Thornton, M., and Olsen, N. 2021. La Belle Russet: an early maturing, dual-purpose variety having a high percentage of marketable yield, long tuber dormancy, and a reduced incidence of sugar ends. American Journal of Potato Research 98:395-410.

Reyes-Corral, C., Cooper, W. R., Horton, D., Miliczky, E., Riebe, J., Waters, T., Wildung, M., and Karasev, A. V. 2021. Association of Bactericera cockerelli (Hemiptera: Triozidae) with the perennial weed Physalis longifolia (Solanales: Solanaceae) in the potato-growing regions of western Idaho. Environmental Entomology 50:1416-1424

Rodriguez-Rodriguez, M., Quintero-Ferrer, A., Green, K. J., Robles-Hernandez, L., Gonzalez-Franco, A. C., and Karasev, A. V. 2021. Molecular and biological characterization of recombinant isolates of Potato virus Y circulating in potato fields in Mexico. Plant Disease 105:2688-2696. https://doi.org/10.1094/PDIS-10-20-2215-RE

Ross, B. T., Zidack, N., and Flenniken, M. L. 2021. Extreme resistance to viruses in potato and soybean. Frontiers in Plant Science 12:658981. https://doi.org/10.3389/fpls.2021.658981

Tran, L., Green, K., Rodriguez-Rodriquez, M., Orellana, G., Funke, C., Nikolaeva, O., Quintero-Ferrer, A., Chikh-Ali, M., Woodell, L., Olsen, N., and Karasev, A. V. 2021. Prevalence of recombinant strains of potato virus Y in seed potato planted in Idaho and Washington states between 2011 and 2021. Plant Disease 106:810-817. https://doi.org/10.1094/PDIS-08-21-1852-SR

Whitworth, J. L., Gray, S. M., Ingram, J. T., and Hall, D. G. 2021. Foliar and tuber symptoms of U.S. potato varieties to multiple strains and isolates of potato virus Y. American Journal of Potato Research 98:93-103. https://doi.org/10.1007/s12230-020-09820-1

Zhang, C., Zarka, K. A., Zarka, D. G., Whitworth, J. L., and Douches, D. S. 2021. Expression of the tomato pot-1 gene confers potato virus Y (PVY) resistance in susceptible potato varieties. American Journal of Potato Research 98:42-50. https://doi.org/10.1007/s12230-020-09815-y

 

Webpages

Potato virus initiative. https://www.uidaho.edu/idaho-ag-experiment-station/potato-virus 

Attachments

Land Grant Participating States/Institutions

AZ, CO, ID, MN, MI, MT, ND, NE, OR, WA, WI

Non-Land Grant Participating States/Institutions

USDA-ARS/Washington

 

Attachments

Land Grant Participating States/Institutions

Non Land Grant Participating States/Institutions