Brief Summary of Minutes of Annual Meeting

WERA-20: VIRUS AND VIRUS-LIKE DISEASES OF FRUIT TREES, SMALL FRUITS, AND GRAPEVINES.

Annual Meeting Minutes
September 18 - 20, 2012 Clemson University Conference Center and Inn
Clemson University, South Carolina.

Participants:Zvezdana Pesic-VanEsbroeck, Erich Rudyj (and wife), Mizuho Nita, Tammy Jones, Sarah Gettys, Bindu Poudel, Lauri Guerra, Carol Masters, Ken Eastwell, Gary Kinard, Simon Scott, John Hu, Annemiek Schilder, Margarita Bateman, Keith Streigler, Yannis Tzanetakis, Michael Kahn, Richard Kaitany, Shulu Zhang, Michael Cunningham, Joseph Postman, Phil Brannen, Ruth Welliver

Tuesday 18th September, 8:30 a.m.

Opening of meeting by host Simon Scott

Welcome by Dr. Joe Culin, Associate Dean of Clemson University College of Agriculture Forestry and Life Sciences.

Simon Scott relayed invitation from Naidu Rayapati to host 2013 meeting

Election of Secretary: Joseph Postman agreed to take minutes if Naidu or someone else would host in 2012.

Comments by Administrative Advisor Michael Kahn: Accepted administrative responsibilities from Ralph Cavalieri. Discussed status of Farm Bill

Reports Presented

Carol Masters (Carol.Masters@inspection.gc.ca) Canadian Food Insp. Agency, Sidney, BC.
Reported on summary of Canadian fruit tree & grape import and export testing for 2010  2012. Plum Pox Virus update: transition in 2012 to industry led management. CFIA monitored quarantine are in Ontario on both sides of the quarantine border. There is a ban on propagation in the quarantine zone. Talked about the possibility of relocation of lab activities from the Sydney quarantine lab.

Yannis Tzanetakis (itzaneta@uark.edu) University of Arkansas, Fayetteville
Reported on what is new and exciting in the world of berry viruses. Blackberry yellow vein disease is rampant in the SE. Attempting to determine the cause and vector. Blackberry leaf mottle associated virus is new Emara virus. This virus group is typically mite transmitted. Positive samples found in 6 southern states. Conventional and quantitative RT-PCR tests have been developed. A mite vector has not been identified, but an eriophyid mite is suspected. A new Ampelovirus in blackberry is closely related to GLRaV-A, a mealybug transmitted virus.

Blueberry Mosaic Disease has been known since 1957, and causes beautiful symptoms but the causal agent has never been identified. A new Ophiovirus has been detected in all mosaic infected plants. This virus group is soil-borne, and a fungus vector is a possibility. A summary was presented on strawberry viruses in North America. There is good industry support for a blueberry certification program, but hesitancy for Rubus certification.

Michael Cunningham (macunningham@ucdavis.edu), Foundation Plant Services, Davis, California.
FPS update. Building expansion in progress. History of Russel Ranch property and status of new grape plantings. Development of tree fruit, strawberry standard operating procedures (distributed copies). Made a presentation for Maher Al Rwahnih on isolation & characterizion of new vitivirus, tentatively named Grapevine virus F (GVF).

Phil Brannen (pbrannen@uga.edu), University of Georgia.
Georgia Virus Disease Report. Grape leafroll became prevalent in N. Georgia about 5-6 years ago. Newly planted vines seem to be more contaminated with virus than older vines, suggesting untrustworthy status of nursery stock used. Discussion about motivating growers & nurseries to participate in certification program. Recently, a new disease was observed on southern highbush blueberries. Initially observed in 2006, plants with symptoms reminiscent of a pathogen-induced disease were found in multiple locations in southeastern Georgia. The disease also has been observed in Florida, Mississippi, South Carolina, and North Carolina.

John Hu (johnhu@hawaii.edu) University of Hawaii, Honolulu.
Update on assorted viruses in Hawaii. Reviewed history of transformation with coat protein to engineer resistance to Papaya ringspot. Deregulated in Japan in 2011, opening the door for expanded exports. Hawaii papaya industry is attempting to get into China too. Banana bunchy-top is most important virus disease of this crop world-wide. Caused by the DNA virus BBTV. Attempts are underway to induce gene silencing with several constructs. Also discussed the status of Huanglongbing (Citrus Greening Disease).

Shulu Zhang (shulu@agdia.com) Agdia Inc., Elkhart, Indiana.
Reported on Development and evaluation of AmplifyRP and ImmunoStrip tests for plum pox virus. Summary provided by Shulu: Agdia Inc. has recently developed AmplifyRP and ImmunoStrip tests for plum pox virus (PPV). Both AmplifyRP exo and AmplifyRP nfo tests are nucleic acid-based isothermal detections of PPV using a recombinase polymerase amplification technology. In contrast, the ImmunoStrip is a protein-based test. Each of these three tests (AmplifyRP exo, AmplifyRP nfo or ImmunoStrip) can detect all currently known six strains (PPV-C, PPV-D, PPV-EA, PPV-M, PPV-Rec or PPV-W) of PPV either in purified plant total RNA preparations or in crude Prunus plant extracts. The AmplifyRP exo, AmplifyRP nfo and ImmunoStrip tests were evaluated and compared to ELISA and RT-PCR. The results demonstrated that the three new tests (AmplifyRP exo, AmplifyRP nfo or ImmunoStrip) are highly sensitive and reliable. In addition, the AmplifyRP exo, AmplifyRP nfo and ImmunoStrip tests are rapid and simple. The whole process from sample preparation to finish for these new tests can be done in as little as 20 minutes. All the new tests do not need thermal cycling and expensive equipment and can be performed in laboratories and in fields.

Annemiek Schilder (schilder@msu.edu), Michigan State University.
Reported on the results of surveys in Michigan for grapevine and blueberry viruses, using Agdia and Bioreba ELISA kits. Shared images of assorted symptoms in grape, seeking input on possible causes. After 2 years of surveys, it appears that Blueberry shock and scorch have been eradicated. Initial survey found BB scorch in a recent Legacy planting that traced back to the nursery source. Later survey found infections in older plantings. Infected plants (plantings?) were destroyed. Bronze leaf curl- a closterovirus?

Zvezdana Pesic-VanEsbroeck (zvezdana_pesic@ncsu.edu), North Carolina State University, Raleigh.
Reported on the Clean Plant Center for Berry Crops at NC State University. The program has a 50 year history working with strawberries. Discussed the protocol for production of G1 Foundation Plants. A new virus (Blueberry latent virus) was recently found in J. Ballingtons collection of plant materials (see: R. R. Martin, J. Zhouc, and I.E. Tzanetakis. 2011. Virus Research 155:175-180).

Simon Scott (sscott@clemson.edu), Clemson University.
Discussed a virus related to Cherry necrotic ring mottle that produced symptoms in rootstock sprouts beneath a tree with symptomless Shirofugen as the scion variety.

Bindu Poudel (bpoudel@g.clemson.edu), Clemson University.
Discussed her PhD project working with S. Scott on Blackberry yellow vein disease, which is associated with a complex of viruses in the SE United States. A new Ilarvirus was found in sentinel plants.

Joseph Postman (Joseph.Postman@ars.usda.gov) USDA-ARS, Corvallis, Oregon.
Reported on the genetic diversity, geographic origins, and virus status of several tree collections at the National Clonal Germplasm Repository in Corvallis. More than 500 tree accessions have been cleaned up at NCGR using heat therapy and meristem culture. Presently, 76% of the 800 Corylus accessions, 83% of 156 Cydonia accessions 79% of 42 Mespilus accessions and 81% of 2171 Pyrus accessions are virus negative.

Meeting Adjourned at 5:00 p.m.  group dinner at Pixie and Bills

Wednesday 18th September, 8:30 a.m. - meeting resumes

Sarah Gettys (sgettys@pa.gov)
Reported on the Pennsylvania Fruit Tree Improvement Program. Summary of various aspects of the PA virus certified tree fruit program. Two certification levels. Developed Pest Management Manual covering procedures. Conduct annual visits (audits). (discussion about nursery practices and fumigation)

Ruth Welliver (rwelliver@pa.gov)
Reported on blueberry shock survey. Samples taken from 12 sites around PA. Found several sites with TomRSV, two farms positive/questionable for Shock and Scorch. Continuing to monitor for Plum Pox. No positive samples since 2006. 40,000 samples tested in 2012. Reviewed eradication efforts. Quarantines have been lifted against growing stone fruits. If all 2012 samples are negative remaining quarantines on nursery production will be lifted.

Margarita L. Bateman (Margarita.L.Bateman@aphis.usda.gov) USDA-APHIS, Beltsville, Maryland
Reported on administrative re-organization of APHIS and position of Plant Protection and Quarantine program. Focus of program is on incoming plant materials from foreign origins. Reviewed testing and therapy protocols and efforts to streamline.

Gary Kinard (Gary.Kinard@ARS.USDA.GOV), USDA-ARS National Germplasm Resources Lab, Beltsville, Maryland.
Development of multiplex TaqMan real-time RT-PCR assay for simultaneous detection of 3 Prunus viroids. Improved elimination of PNRSV from Prunus. Improved elimination of Rubus viruses. Factorial experiments looking at combinations of temperature and antiviral chemicals. Budget, International Treaty, GRIN-Global, Pathologist vacancy comments.

Ken Eastwell (keastwell@wsu.edu), Clean Plant Center of the Northwest, Washington State University.
Foundation programs for fruit trees, grapevines, hops and ELISA lab organized into single administrative "center". Discussion about Little Cherry, Cherry leaf roll, Cherry raspleaf, Betaflexiviridae in sweet cherry. Unusual expansion of little cherry, even in normally tolerant varieties like Bing. Cherry leafroll is spreading. Alternate reservoirs are in Elderberry and Rhubarb.

Mizuho Nita (nita24@vt.edu), Virginia Tech, Winchester, VA.
Virus diseases not as obvious when fungal diseases require attention. Reported on grape virus survey in Virginia. Leafroll 3 was most prevalent. Used cluster analysis to suggest vector, cultivar and virus relationships for several grape viruses.

Erich Rudyj (Erich.S.Rudyj@aphis.usda.gov) NCPN Riverdale, Maryland.
History and status of National Clean Plant Network. Farm Bill update relative to NCPN funding.

Keith Streigler (keith@flintridgewinegrowingservices.com).
NCPN Education and Outreach summary. Facilitates national working group to develop communication plans. Specialty crop brochures need regular updates. PowerPoint Presentation that can be used by the NCPN community.

Meeting concluded at noon.

Box lunches while traveling to Boiling Springs, SC to view blackberry viruses at Mr. James Cooleys Strawberry Hill Farm (cvs Ouachita and Navaho).

Travel to a recent planting of Primark 45 at Mr. Jose Landas Farm.

Thursday, 20 September

The group visited 3 wineries in Northeast Georgia: Blackstock Winery, Wolf Mountain Winery, and Frogtown Winery. Symptoms of Pierce's disease and plants displaying symptoms typical of infection by grapevine leaf roll virus were seen.

To view full 2012 individual state reports, go to WERA-20's Homepage under the Additional Documents Section at the following address: http://lgu.umd.edu/lgu_v2/homepages/attachs.cfm?trackID=13496

Grapevines: Research by members of the project in Idaho, Washington, and Michigan on grapevines, and the viruses that infect them, provided evidence; 1) that Grape vine leaf roll associated virus 1 (GLRaV-1) occurs as genetically distinct variants in the three leading grapevine-producing states of the U.S.: California, New York and Washington, New York; 2) that Grapevine leaf roll disease (GLRD) - associated with a complex of Grape vine leaf roll associated viruses - has negative impacts on vine performance and the quality of grapes produced by own-rooted Merlot grapevines; and 3) Grapevine fleck virus (GFkV) previously identified in Washington is also present in Idaho and Michigan.

Cherry: Cherry orchards in the northwest are affected by a number of different viruses of economic importance: Little cherry virus 2, Cherry leaf roll virus, Cherry Rasp Leaf virus, and the rusty mottle group of viruses. Research has identified Grape mealybug (Pseudococcus maritimusis) as a previously unsuspected vector of Little cherry virus 2 that may be contributing to the recent increase of the spread of this virus within the industry. Ongoing research demonstrates that the 'Colt' rootstock represents the best protection available to growers for Cherry leaf roll virus. Blue elderberry (Sambucus nigra) has been identified as a previously unrecognized reservoir host for Cherry rasp leaf virus and this may account for the persistence of the virus in the central Washington growing area where elderberry is abundant in valley vegetation. Molecular characterization of Cherry necrotic rusty mottle virus indicates that it may be part of a unique genus of viruses. Furthermore, the virus has been detected in a flowering cherry growing in South Carolina for the first time on. There is no cherry industry in this state but flowering cherries are frequently planted in the landscape which raises the question as to whether they act as a source of the virus that is readily moved around the nation.

The majority of testing for viruses in the crops covered by WERA-20 is accomplished using PCR. Although most labs are equipped with thermocyclers, and PCR is routine in many locations, new technologies are being exploited to expand the scope of sensitive testing techniques. Recombinase polymerase amplification technology is a nucleic acid-based test completed at a single temperature, obviating the need for thermocyclers, and thus can be performed both in laboratories and in the field in as little as 20 minutes. Agdia has demonstrated the utility of this system with Plum Pox virus.

Publications

Janse, J.D., Valentini, F., Purcell, A.H. and Almeida, R.P.P. 2012. Detection and identification methods and news tests as used and developed in the framework of COST873 for bacteria pathogenic to stone fruits and nuts: Xylel la fastidiosa. Journal of Plant Pathology 94: S1.147-154. Tsai, C.W., Daugherty, M.P. and Almeida, R.P.P. 2012. Seasonal dynamics and virus translocation of Grapevine leafroll-associated virus 3 in grapevine cultivars. Plant Pathology 61: 977-985. Daane, K.M., Almeida, R.P.P., Bell, V.A., Botton, M., Fallahzadeh, M., Mani, M., Miano, J.L., Sforza, R., Walton, V.M. and Zaveizo, T. 2012. Biology and management of mealybugs in vineyards. p. 271-307. In: N.J. Bostanian et al. (eds.) Arthropod Management in Vineyards: Pests, Approaches, and Future Directions. Springer. 505p. Almeida, R.P.P., Killiny, N., Newman, K.L., Chatterjee, S., Ionescu, M. and Lindow, S.E. 2012. Contribution of rpfB to cell-cell signal synthesis, virulence, and vector transmission of Xylella fastidiosa. Molecular Plant-Microbe Interactions 25: 453-462. Killiny, N., Rashed, A. and Almeida, R.P.P. 2012. Disrupting the transmission of a vector-borne plant pathogen. Applied and Environmental Microbiology 78: 638-643. Daugherty, M.P., Gruber, B.R., Almeida, R.P.P., Anderson, M.M., Cooper, M.L., Rasmussen, Y. and Weber, E. 2012. Testing the efficacy of barrier plantings for limiting sharpshooter spread. American Journal of Enology and Viticulture 63: 139-143. Daane, K.M., Middleton, M.C., Sforza, R., Cooper, M.L., Walton, V.M., Walsh, D.B., Zaviezo, T. and Almeida, R.P.P. 2011. Development of a multiplex PCR for identification of vineyard mealybugs. Environmental Entomology 40: 1595-1603. Tsai, C.W., Bosco, D., Daane, K.M. and Almeida, R.P.P. 2011. Effect of host plant tissue on the vector transmission of Grapevine leafroll-associated virus 3. Journal of Economic Entomology 104: 1480-1485. Rashed, A., Daugherty, M.P. and Almeida, R.P.P. 2011. Grapevine genotype susceptibility to Xylella fastidiosa does not predict vector transmission success. Environmental Entomology 40: 1192-1199. Sharma, A.M., Wang, J., Duffy, S., Zhang, S., Wong, M.K., Rashed, A., Cooper, M.L., Daane, K.M. and Almeida, R.P.P. 2011. Occurrence of grapevine leafroll-associated virus complex in Napa Valley. PLoS ONE 6: e26227. Killiny, N. and Almeida, R.P.P. 2011. Gene regulation mediates host specificity of a bacterial pathogen. Environmental Microbiology Reports 3: 791-797. Daugherty, M.P., Rashed, A., Almeida, R.P.P. and Perring, T.M. 2011. Vector preference for hosts differing in infection status: sharpshooter movement and Xylella fastidiosa transmission. Ecological Entomology 36: 654-662. Plucinski, M.M., Starfield, R. and Almeida, R.P.P. 2011. Inferring social network structure from bacterial sequence data. PLoS ONE 6: e22685. Gutierrez, A.P., Ponti, L., Hoddle, M., Almeida, R.P.P. and Irvin, N.A. 2011. Geographic distribution and relative abundance of the invasive glassy-winged sharpshooter: effects of temperature and egg parasitoids. Environmental Entomology 40: 755-769. Kung, S.H. and Almeida, R.P.P. 2011. Natural competence and recombination in the plant pathogen Xylella fastidiosa. Applied and Environmental Microbiology 77: 5278-5284. Coletta-Filho, H.D., Bittleston, L.S. and Almeida, R.P.P. 2011. Spatial genetic structure of a vector-borne generalist pathogen. Applied and Environmental Microbiology 77: 2596-2601. Degnan, P.H., Bittleston, L.S., Hansen, A.K., Sabree, Z.L., Moran, N.A. and Almeida, R.P.P. 2011. Origin and examination of a leafhopper facultative endosymbiont. Current Microbiology 62: 1565-1572. Rashed, A., Killiny, N., Kwan, J. and Almeida, R.P.P. 2011. Background matching behaviour and pathogen acquisition: Plant site preference does not predict bacterial acquisition efficiency by vectors. Arthropod-Plant Interactions 5: 97-106. Wang, J., Sharma, A.M., Duffy, S. and Almeida, R.P.P. 2011. Genetic diversity in the 3' terminal 4.7-kb region of Grapevine leafroll-associated virus 3. Phytopathology 101: 445-450. Liming Lin, Ruhui Li, Ray Mock, and Gary Kinard, 2012. One-Step multiplex RT-PCR for simultaneous detection of four pome tree viroids. European Journal of Plant Pathology 133: 765-772. Wei-Li Rao, Fan Li, Ruijuan Zuo and Ruhui Li, 2011. First Report of Little cherry virus 2 in Flowering and Sweet Cherry Trees in China. Plant Disease 95: 1484. Schilder, A., and Brown-Rytlewski, D. Virus and Virus-like diseases in Grapes. MSU Extension, Michigan State University (in preparation). Schilder, A. 2011. Blueberry Scorch Virus. Regional Pest Alert, North Central IPM Center, 2 pp. Schilder, A. 2011. Blueberry Shock Virus. Regional Pest Alert, North Central IPM Center, 2 pp. Isaacs, R., Schilder, A., Zabadal, T., and Weigle. T. 2011. A pocket guide for grape IPM scouting in the North Central and Eastern U.S. Michigan State University Extension Bulletin E-2889. 4th Edition. Wise, J. C., Gut, L. J., Isaacs, R., Schilder, A. M. C., Sundin, G. W., Zandstra, B., Hanson, E., and Shane, B. 2011. Michigan Fruit Management Guide 2012. Extension Bulletin E-154. Michigan State University, East Lansing, MI. Eastwell KC, Druffel KL. 2012. Complete genome organization of American hop latent virus and its relationship to carlaviruses. Arch Virol 157:14031406 Eastwell KC, Mekuria TA, Druffel KL. 2012. Complete nucleotide sequences and genome organization of a cherry isolate of cherry leaf roll virus. Arch Virol 157:761764 Alabi, O. J., Al Rwahnih, M., Karthikeyan, G., Poojari, S., Fuchs, M., Rowhani, A., and Naidu, R. A. 2011. Grapevine leafroll-associated virus 1 occurs as genetically diverse populations. Phytopathology 101: 1446-1456. Rayapati, N.A., ONeil, S. and Walsh, D. 2011.Grapevine leafroll disease (la enfermedad del enrollamientode la hoja de parra) in Spanish (EB2027ES). Naidu, R.A. 2011. Virus Diseases. In: 2011 Pest Management Guide for Grapes in Washington. WSU Extension Bulletin EB0762, pp.25-28. Naidu, R.A. 2011. Virus update: The Status of Washington Vineyards. In: Viticulture and Enology Extension News Fall 2011.

You Tube Videos:

Grapevine Leafroll Disease Symptoms (http://wine.wsu.edu/research-extension/grape-growing/plant-health/virology/; http://www.youtube.com/watch?v=Es41Tdgd9L0&NR=1&feature=endscreen) Grapevine Disease: Be Clean, Stay Clean (http://www.youtube.com/watch?v=Vt_OyWpXohE&feature=related) How Grapevine Virus Diseases Spread: 4 propagation methods https://www.youtube.com/watch?v=605YHdIeSC8