Brief Summary of Minutes of Annual Meeting

Joe Munyaneza - Chair Nina Zidack - Vice-Chair (not present) Alex Karasev - Secretary On March 15, 2012, Joe Munyaneza (Chair) opened the meeting at 8:00 am, briefly presented the agenda, and reported that the group administrative advisor, Donn Thill, Director of the Idaho Agricultural Experiment Station, was unable to attend in person, but would be able to connect by phone later. Participants introduced themselves. Minutes of the 2011 meeting in Tucson, AZ, were moved for approval by the chair, seconded, and approved by unanimous vote. The agenda started with state reports, following tradition of WERA-89. Colorado - Kent Sather described the past season as slow starting, with cool weather early in the season, and record year for green peach aphids. Most seed lots rejected were rejected due to PVY, and these mainly Norkotahs and Fingerlings. No Zebra Chip found in San Luis Valley in 2011. Seed test plots in Yuma, AZ, affected by cold weather, results were sent to growers by February 20. Current tag tolerance for CO is 10% for PVY; but 20% of RN lots had levels exceeding 10% PVY. One lot had PLRV, this was an organic seed lot. Washington - Mark Pavek reviewed the Othello, WA, trials during 2011. Montana currently is the main source of potato seed, with Russet Burbank being the main cultivar planted. However, the share of RB decreases over the years. The number of new cultivars planted keeps going up. Mosaic and blackleg remain steady from 2010. PLRV was not found; PLRV suppression efforts were efficient so far. In the discussion, after the presentation, Mark noted that Norkotahs continue to be the highest source of PVY. Idaho - Phil Nolte gave an overview of the 2011 winter grow-out results. Idaho had an uptick in the PVY level, the number of seed lots rejected for re-certification increased to the 2009 level. Previously, the rejection rate decreased every year since 2007. This persistent decrease was attributed to the implementation of the mandatory ELISA testing in the winter grow-out, introduced in 2006. Discussion followed to try to explain the reasons for the uptick. Possible reasons mentioned were new varieties, climatic factors, or changes in practices (organic potato). Idaho had its first official Zebra Chip find in 2011, but left details for a later presentation. Montana - Susie Siemsen reported that no Zebra Chip was found in 2011 in Montana. Montana saw increased levels of PVY in winter grow-out tests relative to summer inspections. She blamed mild fall and slow season's start; hence growers were late with vine kill, which perhaps promoted late aphid flight and late infections not visible on foliage. Applications of insecticides to control PVY do not work. California - Pablo Guzman reported that he saw ZC in CA (1 grower). Nebraska - Steve Marquardt reported that NE is doing large scale psyllid testing; last year's population was low but this year they saw an increase in psyllid numbers. They are usually found in the fields the first week of June. Green peach aphids were rarely seen. They saw an increase in PVY, 3-5% in the winter grow-out test. Oregon - Jordan Eggers reported data from the Oregon winter grow-out. There were 27 OR lots, four lots with mosaic (Shepody and Norkotahs) and two WA seed lots with mosaic. Canada - Mathuresh Singh presented field research data on controlling PVY spread with mineral oil spray applications. This is a very promising strategy in Canada, but timing of application is very important. Donn Thill - connected to the meeting via telephone conference - complimented WERA-89 for successful work over the years, informed that WERA-89 was renewed last year and thus has another 4 years to go. Donn also instructed the members on timely submission of impact statements for the group's activities. He reported on the Federal budget situation as it related to potato pathology, including proposed reductions for ARS. In the discussion, Donn explained that the Specialty Crop Research Initiative program will likely continue to be supported through the upcoming Farm Bill. The old Farm Bill will probably be extended for 1 year, until a new one is approved. After Dr. Thill's presentation, state and research reports resumed.

Alex Karasev - presented 2011 data from the Othello, WA, trials focused on PVY testing and typing. These trials include potato seed coming from several PNW states and Canada. Most of the mosaic samples (ca. 90%) were PVY-positive. Typing of these PVY samples suggested clustering of the isolates from recombinant strains to specific cultivars and producers. Recombinant, NTN isolates were found in seed potato from WA, OR, ID, and MT, as well as in seed from Canada. Similar typing was conducted with Phil Hamm at Hermiston, OR; trial samples gave similar results. Stewart Gray gave an overview of the PVY strain composition across all states, and changes over time. In 2004-2006, a national survey was conducted. At that time, a substantial proportion of NTN was found in only one state. Since 2009, select states were surveyed through the SCRI surveys. NTN showed up in more and more states and in more seed lots every year. N:O type seems to be replacing O type. Summer inspections are not very efficient due to late season infections that do not induce foliar symptoms. Winter grow-out test is a real measure of what is present at harvest time. Discussion ensued on possible strategies to control NTN types; one way would be to identify and remove NTN-infected lots from seed production. Jonathan Whitworth described experiments on the correlation between visual symptom expression and actual PVY infection determined by ELISA. Experiments were conducted during the Idaho winter grow-out testing this past winter. It is difficult to correlate when ELISA signals are low. The second half of the day was focused on discussion of Zebra Chip disease and new areas affected by ZC in 2011. Joe Munyaneza gave a historical overview of the ZC emergence in Mexico in early 1990s, gradually spreading to Texas and further north and west. Joe described symptoms of the disease, pathogenesis, vector (psyllid), and effect on tuber yield and quality. Overall, it is a devastating disease with a huge loss potential for the potato industry. He specifically talked about possible effects on potato seed production. The conclusion is that ZC is not at the moment a threat to the seed production, since infected plants do not normally produce viable tubers, and if a tuber sprouts and a plant emerges, it is not infected. This finding contradicts data from New Zealand, but perhaps the reason is over-reliance of New Zealand researchers on real time PCR. Joe described the 2011 ZC outbreak in Washington. Only select spots were affected, 40 miles apart, locations had or did not have ZC in similar potato fields. Origin of infected psyllids is not known, but it is unlikely that it is from Texas. Psyllids may be able to overwinter in Idaho, experiments are ongoing. Phil Hamm reviewed the 2011 outbreak of ZC in Oregon and Washington. Initial infected psyllids probably arrived June 20-25, 2011, but first foliar symptoms were noticed in mid-July. First tuber symptoms were reported the week of August 22. Phil showed infrared pictures of the affected circles, at different dates, demonstrating disease spread from a few initial infection foci. He discussed if this problem happened because of a long, no insecticide treatment period. During the discussion it was brought up that some insecticides, pyrethroids, may actually excite psyllids and promote ZC spread. Phil described effect of ZC on variety trial plots, with some cultivars surviving the infection. Also, he reported on finding ZC in gardens around Hermiston, in tomato, tomatillo, and peppers. Lessons for 2012: Spraying, management of volunteers, and monitoring for symptomatic plants. Silvia Rondon described studies on ZC conducted at the Hermiston station. Experiments on potential overwintering hosts for psyllids showed that bittersweet nightshade is an overwintering host; other weeds may potentially serve for overwintering as well. Experiments are in progress on testing all these weeds for Liberibacter. Silvia talked about methods to monitor psyllids in the field, and about appropriate chemicals for psyllid control. Don Henne described the situation with ZC in Texas. In Texas, he never sees ZC symptoms before bloom. ZC shows up in clusters, edges are affected much more. He discussed how to monitor psyllids; no good recommendation/device so far. Pyrethroids are not used for psyllid control due to the "flare-up" effect on insects. Early season management is crucial to minimize damage.

Buchman JL, Sengoda VG & Munyaneza JE. 2011. Vector transmission efficiency of liberibacter by Bactericera cockerelli (Hemiptera: Triozidae) in zebra chip potato disease: effects of psyllid life stage and inoculation access period. Journal of Economic Entomology 104: 1486-1495. Buchman JL, Heilman BE & Munyaneza JE. 2011. Effects of Bactericera cockerelli (Hemiptera: Triozidae) density on zebra chip potato disease incidence, potato yield, and tuber processing quality. Journal of Economic Entomology 104: 1783-1792. Buchman, JL, TW Fisher, VG Sengoda, and JE Munyaneza. 2012. Zebra chip progression: from inoculation to potato plants with liberibacter to development of disease symptoms in tubers. American Journal of Potato Research 89: 159-168. Cilia, M., C. Tamborindeguy, T. Fish, K. Howe, T. W. Thannhauser, and S. Gray, 2011. Genetics Coupled to Quantitative Intact Proteomics Links Heritable Aphid and Endosymbiont Protein Expression to Circulative Polerovirus Transmission. J. Virol., 85: 2148 - 2166. Cilia, M., Howe, K., Fish, T., Smith, D., Mahoney, J., Tamborindeguy, C., Burd, J., Thannhauser, T., and Gray, S. M. 2011. Biomarker discovery from the top down: Protein biomarkers for efficient virus transmission by insects (Homoptera: Aphididae) discovered by coupling genetics and 2-D DIGE. Proteomics 11:2440-2458. Crosslin, J.M., P.B. Hamm, J.E. Eggers, S.I. Rondon, V.G. Sengoda, and J.E. Munyaneza. 2012. First report of zebra chip disease and "Candidatus Liberibacter solanacearum" on potatoes in Oregon and Washington State. Plant Dis. 96:452. Crosslin, J.M., S.I. Rondon, and P.B. Hamm. 2012. Population dynamics of the beet leafhopper in northeastern Oregon and incidence of the beet leafhopper-transmitted virescence agent phytoplasma. Am. J. Pot. Res. 89:82-88. Crosslin, J.M., N. Olsen, and P. Nolte. 2012. First report of zebra chip disease and "Candidatus Liberibacter solanacearum" on potatoes in Idaho. Plant Dis. 96:453. Crosslin, J.M. 2011. First report of Potato mop-top virus on potatoes in Washington State. Plant Dis. 95:1483. Crosslin, J.M., L.L. Hamlin, J.L. Buchman, and J.E. Munyaneza. 2011. Transmission of potato purple top phytoplasma to potato tubers and daughter plants. Am. J. Pot. Res. 88:339-345. Crosslin, J.M., and L.L. Hamlin. 2011. Standardized RT-PCR conditions for detection and identification of eleven viruses of potato and Potato spindle tuber viroid. Am. J. Pot. Res. 88:333-338. Crosslin, J.M., H. Lin, and J.E. Munyaneza. 2011. Detection of 'Candidatus Liberibacter solanacearum' in potato psyllids, Bactericera cockerelli Sulc, by conventional and real-time PCR. Southwest. Entomol. 36:125-135. Karasev, A.V., Hu, X., Brown, C.J., Kerlan, C., Nikolaeva, O.V., Crosslin, J.M., and Gray, S.M. 2011. Genetic diversity of the ordinary strain of Potato virus Y (PVY) and origin of recombinant PVY strains. Phytopathology 101: 778-785. Kerlan, C., Nikolaeva, O., Hu, X., Meacham, T., Gray, S., and Karasev, A. 2011. Identification of the molecular make-up of the Potato virus Y strain PVYZ. Phytopathology 101:1052-1060. Cavatorta, J., Perez, K., Gray, S., Van Ek, J., Yeam, I., and Jahn, M. 2011. Engineering virus resistance using a modified potato gene. Plant Biotech. J. 9:1014-1021. Galvino-Costa, S.B., Figueira, A., Camargos, V.V., Geraldino, P.S., Hu, X., Nikolaeva, O.V., Kerlan, C., and Karasev, A.V. 2012. A novel type of Potato virus Y recombinant genome, determined for the genetic strain PVYE. Plant Pathology 61: 388-398. Ibolya, E., Z. Acs, J.E. Munyaneza, J.M. Crosslin, and M. Kolber. 2011. Survey and molecular detection of phytoplasmas associated with potato in Romania and Southern Russia. European Journal of Plant Pathology 130: 367-377. Ju, H.J., Van Eck, J., and Gray, S.M. 2011. Factors influencing plant regeneration from seedling explants of Hairy Nightshade (Solanum sarrachoides). Plant Cell Tiss Organ Cult. 108:121-128. Mello, A.F.S., Olarte, R.A., Gray, S.M., and Perry, K.L. 2011. Transmission efficiency of Potato virus Y strains PVYO and PVYN-Wi by five aphid species. Plant Dis. 95:1279-1283. Lacey, L.A., T.X. Liu, J.L. Buchman, J.E. Munyaneza, J.A. Goolsby, and D.R. Horton. 2011. Entomopathogenic Fungi (Hypocreales) for Control of Potato Psyllid, Bactericera cockerelli (`ulc) (Hemiptera: Triozidae) in an Area Endemic for Zebra Chip Disease of Potato. Biological Control 56: 271-278. Liu Q, C Jianchi, J.E. Munyaneza, and E.L. Civerolo. 2011. Endophytic bacterial in potato tubers affected by zebra chip disease. American Phytopathological Society 101: S108. Munyaneza, J.E., A. Lemmetty, A.I. Nissinen, V.G. Sengoda, and T.W. Fisher. 2011. Molecular detection of aster yellows phytoplasma and 'Candidatus Liberibacter solanacearum' in carrots affected by the psyllid Trioza apicalis (Hemiptera: Triozidae) in Finland. Journal of Plant Pathology 93: 697-700. Munyaneza JE, Sengoda VG, Buchman JL & Fisher TW. 2012. Effects of temperature on 'Candidatus Liberibacter solanacearum' and zebra chip potato disease symptom development. Plant Disease 96: 18-23. Munyaneza JE, Buchman JL, Sengoda VG, Fisher, TW & Pearson CC. 2011. Susceptibility of selected potato varieties to zebra chip potato disease. American Journal of Potato Research 88: 435-440. Munyaneza, JE, VG Sengoda, L Sundheim, and R Meadow. 2012. First report of 'Candidatus Liberibacter solanacearum' associated with psyllid-affected carrots in Norway. Plant Disease 96: 454. Munyaneza, JE, VG Sengoda, R Stegmark, AK Arvidsson, O Anderbrant, JK Yuvaraj, B Ramert, and A Nissinen. 2012. First report of 'Candidatus Liberibacter solanacearum' associated with psyllid-affected carrots in Sweden. Plant Disease 96: 453. Nikolaeva, O.V., Roop, D., Galvino-Costa, S.F.B., Figueira, A.R., Gray, S.M., and Karasev, A.V. 2012. Epitope mapping for monoclonal antibodies recognizing tuber necrotic strains of Potato virus Y. American Journal of Potato Research 89: 121-128. Peng, L., J.T. Trumble, J.E. Munyaneza, and T.X. Liu. 2011. Repellency of a kaolin particle film to potato psyllid, Bactericera cockerelli (Hemiptera: Psyllidae) on tomato under laboratory and field conditions. Pest management Science 67: 815-824. Webpage: Grey, S. Charkowski, A., Groves, R., Hutchinson, P., Karasev, A., McIntosh, C., Nolte, P., Whitworth, J. Updated Yearly. Managing Potato Virus Y in Seed Potato Production. http://www.potatovirus.com.