SAES-422 Multistate Research Activity Accomplishments Report
Sections
Status: Approved
Basic Information
- Project No. and Title: WERA_OLD20 : Virus and virus like diseases of fruit trees, small fruits and grapevines
- Period Covered: 10/01/2002 to 09/01/2003
- Date of Report: 12/08/2003
- Annual Meeting Dates: 11/17/2003 to 11/19/2003
Participants
Part I. Opening Remarks and Business Meeting:
John Hu, chair of WCC20, called the meeting to order.
Ralph Cavalieri, WCC20 Administrative Advisor, welcomed participants. He mentioned that reporting was the only administrative requirement for WCC20 this year. Ralph discussed the need to let Experiment Station Directors know if germplasm and NRSP5 are important to their research, or funding for these programs through CSREES will disappear.
It was announced that Adib Rowhani has agreed to chair and host WCC20 next year, holding the meeting in Davis CA in the third week of May. NRSP5 will meet jointly with WCC20 in Davis.
Special thanks to Ralph Scorza, Ruth Welliver, John Halbrendt, and the NE1006 (Plum Pox) planning committee for proposing the joint meeting with their group this year.
Special thanks to Ruth Welliver for taking notes and preparing the annual report of the 2003 annual meeting.
Special recognition and thanks to Dr. Baozhong Meng, who worked hard to set up and organize the meeting and field trips for May 2003, that were so sadly cancelled due to potential problems with SARS. Our thanks to Dr. Meng and his colleagues for the effort expended.
Other Meeting Activities:
Joint meeting of NE1006, November 17-18, 2003
Many WCC20 attendees also participated in the NE1006 meeting. NE1006 is the project on Eradication, Containment and/or Management of Plum Pox Disease (Sharka). In this meeting, talks were given that summarized survey data for work in both the United States and Canada. Research reports were presented on host range, strain characterization, transmission, epidemiology, and detection of virus. Work developing transgenic resistance and its underlying mechanism was described. An outline of the regulatory process surrounding PPV as a select agent under the Ag Bioterrorism Prevention Act of 2002 was provided. Finally, research information transfer via university extension projects and certification initiatives were discussed. Dr. Michel Ravelonandro, from INRA, Bordeaux, France, was an invited speaker who presented an overview of plum pox virus in Europe. Approximately 100 people participated the NE1006 annual meeting.
Tour: A tour of the Appalachian Fruit Research Station was offered to all interested parties.
John Hu, chair of WCC20, called the meeting to order.
Ralph Cavalieri, WCC20 Administrative Advisor, welcomed participants. He mentioned that reporting was the only administrative requirement for WCC20 this year. Ralph discussed the need to let Experiment Station Directors know if germplasm and NRSP5 are important to their research, or funding for these programs through CSREES will disappear.
It was announced that Adib Rowhani has agreed to chair and host WCC20 next year, holding the meeting in Davis CA in the third week of May. NRSP5 will meet jointly with WCC20 in Davis.
Special thanks to Ralph Scorza, Ruth Welliver, John Halbrendt, and the NE1006 (Plum Pox) planning committee for proposing the joint meeting with their group this year.
Special thanks to Ruth Welliver for taking notes and preparing the annual report of the 2003 annual meeting.
Special recognition and thanks to Dr. Baozhong Meng, who worked hard to set up and organize the meeting and field trips for May 2003, that were so sadly cancelled due to potential problems with SARS. Our thanks to Dr. Meng and his colleagues for the effort expended.
Other Meeting Activities:
Joint meeting of NE1006, November 17-18, 2003
Many WCC20 attendees also participated in the NE1006 meeting. NE1006 is the project on Eradication, Containment and/or Management of Plum Pox Disease (Sharka). In this meeting, talks were given that summarized survey data for work in both the United States and Canada. Research reports were presented on host range, strain characterization, transmission, epidemiology, and detection of virus. Work developing transgenic resistance and its underlying mechanism was described. An outline of the regulatory process surrounding PPV as a select agent under the Ag Bioterrorism Prevention Act of 2002 was provided. Finally, research information transfer via university extension projects and certification initiatives were discussed. Dr. Michel Ravelonandro, from INRA, Bordeaux, France, was an invited speaker who presented an overview of plum pox virus in Europe. Approximately 100 people participated the NE1006 annual meeting.
Tour: A tour of the Appalachian Fruit Research Station was offered to all interested parties.
Accomplishments
Part II. State Reports
Dan Thompson, CFIA Centre for Plant Health, Sydney, B.C. During the NE1006 portion of the meeting, Dan presented an update on host range studies for the Canadian isolates of PPV. During WCC20, he reported on work to optimize a system for detection of fruit tree phytoplasmas by PCR, utilizing the same RNA extraction also used for virus PCR tests. Dan found the test fairly reliable from early June through October, using either RNA or DNA extraction.
Roberto Michelutti, Agriculture and Agri-Food Canada Clonal Genebank, Harrow, Ontario, reported on testing for viruses in Fragaria, Rubus, Malus, Pyrus, and Prunus in their collection. Two years of plum pox screening have yielded all negative results. In collaboration with colleagues in Spain and Italy, Roberto used a tissue printing assay for PLMVd, hop stunt viroid, and PPV.
Deborah Golino, Foundation Plant Services, UC-Davis, showed work on experimental transmission of two closteroviruses (grapevine leafroll-associated Virus 5 and 9) by Longtailed Mealybugs. She discussed the complexity of the system and the difficulty in identifying singlely-infected plants. She also mentioned that a relatively new mealybug species to CA (the vine mealybug) is changing the dynamics of the system.
Jerry Uyemoto, USDA-ARS, UC-Davis gave an update on the rootstock genotypes that react with Redglobe virus (GLRaV-2 RG). The virus kills five rootstocks within two dormancy periods. Jerry recommends that, to properly monitor for virus disease agents, numbers of biological indicators should increase rather than decrease.
In tree fruits, Jerry showed three separate instances of the occurrence of Cherry Virus A in CA, each in combination with other viruses and with different symptoms. He also described a Bing cherry with cherry necrotic rusty mottle foveavirus, and graft-transmissible Plum Bark Necrosis Stem Pitting on black beaut.
John Hu, from the University of Hawaii, presented his work on survey and control of Citrus Tristeza Virus (CTV) in Hawaii. CTV isolates have been collected and characterized at the serological and molecular level. Significant strain diversity exists in Hawaii: variation within and between groups is 91% with HI and foreign alignments, even excluding outliers from the analysis. Development of transgenic plants with broad resistance is a current goal, using a chimeric transgene approach in the Mexican Lime regeneration system. Johns group is also evaluating local CTV strains as cross protection candidates, and has identified several promising mild isolates.
Harold Larsen, Colorado, discussed local industry changes the apple industry is shrinking in size; peach now #1, apple #2, wine grape #3 in acreage. Harold is now 65% viticultural support powdery mildew in grape and bloom delay in grapes. Increasing interest in sweet cherries. Have cherry raspleaf (in peach, cherry, apples). Would like to see development of rootstocks with resistance to CRLV acquisition. Harold showed images of grape displaying a necrotic vein symptom of unknown etiology, as well as some suspected chemical injury and other pests in grape. Peach mosaic and peach wart have not been seen in recent years.
Ray Mock, USDA-ARS Plant Germplasm Quarantine Office, Maryland, described administrative changes in their unit, staffing shortages, and an update on their building project. This year, imports received were very near their maximum capacity, and many releases were made, with a large number of samples still in process in therapy and testing via standard regimen. The unit intercepted disease agents in pome fruits, stone fruits, and small fruit.
The molecular research lab, under the guidance of Dr. Li, is developing new methods for testing, currently working with CGRMV and CNRMV in Prunus, blackcurrant reversion and gooseberry vein banding virus in Ribes.
Ruhui Li USDA-ARS Plant Germplasm Quarantine molecular research lab, Maryland, provided a research report on detection of cherry green ring mottle and cherry necrotic rusty mottle foveavirus by rt-pcr. The original objective of the research was to investigate replacement of biological assay with pcr. Using sequences from both viruses, Dr. Li developed consensus primer sequences for the two viruses, and developed a fast, simple, and reliable RNA prep method.
Ramon Jordan, USDA-ARS, Beltsville, Maryland, mentioned that he was working to identify potyviruses that react in the Durviz PPV ELISA test. Preliminary evidence points to a Tulip-breaking-like virus in lily, tested originally by John Halbrendt in Pennsylvania, that cross-reacts.
Annemiek Schilder, Michigan State Univ., reported on fruit virology activities in Michigan. Annemiek provides diagnostic support for small fruit growers. Blueberry disease symptoms have increased in 2003: shoestring predominant, with some tobacco ringspot, stunt suspected but not confirmed, and virus-like symptoms cold injury in blueberries, potato leafhopper in raspberries. Tobacco ringspot finds in table grape planting stock initiated a program of screening mother blocks and propagating virus-free planting material. Virus-free blueberry nursery program is also available and expanding.
Annemiek summarized MI Dept. of Agriculture program testing pome and stone fruit nursery stock, a Michigan breeding program for virus tolerance in sweet cherries, a research program on virus-mediated resistance in cherries, work with the blueberry red ringspot promoter as an alternative to CaMV 35S, and development of a new IPM scouting guide for grape.
Gene Milbrath, OR Department of Agriculture, summarized work in Bob Martins lab, Corvallis. All blueberry coming into state must be tested for blueberry scorch, in an effort to prevent more aggressive strains from becoming established. Bob is investigating possibility of blueberry scorch in cranberries. He is also working with whitefly-transmitted viruses in small fruits blackberry yellow vein-associated virus appears to have been distributed across southeast from Arkansas breeding program, beet pseudo-yellows virus in blackberries from southeast and in strawberries from CA and MD. Aphid-borne viruses in strawberry from NW cause severe decline in one variety of strawberry that was developed as a tolerant variety.
ODA plum pox survey has concentrated in orchards around nurseries, rather than nurseries themselves, in 2003; did special pumiselect sampling as part of traceback work for a positive in PA. All PPV testing of Oregon material negative. 26 nurseries in certification testing for ilars and ToRSV. Becoming a large ornamentals program with fruit trees declining. Did do cherry leafroll survey in Oregon cherry orchards. Some suspicious symptoms, but all tested negative.
Simon Scott, Clemson University, South Carolina, gave a status report on work with Ta Tao varieties and their associated viruses and viroids. He is attempting to tease out the components of the system that result in bloom delay in Ta Tao and related Chinese genetic resources. So far, various combinations of Asian Prunus Latent Virus, perhaps several other foveaviruses, peach latent mosaic viroid, and apple chlorotic leafspot virus have been implicated. Simon is also experimenting with Okinawa rootstock as an indicator plant for various Prunus viruses. During NE1006 portion of meetings, Simon also presented information on PPV sampling and testing of fruit all negative.
John Halbrendt, Pennsylvania State University, and Ruth Welliver, PA Dept. of Agriculture, both presented information on 2003 PA plum pox work during the NE1006 portion of the meeting. In addition, they mentioned an apple decline situation they are investigating.
Bill Howell, NRSP5, Washington state (with input from Laurri Guerra, WA Dept. of Agriculture), discussed the emergence of Cherry Leafroll Virus decline disease in sweet cherry. Disease can be even more severe in mixed infection with ilarviruses. Washington state fruit commission worked to clean up orchards through educational/survey program involving extension, fruit packing warehouse fieldmen, and growers. Removing diseased trees must use herbicide to detect root grafts (see herbicide damage the next spring), and insecticide to kill vectors before removing trees in summer time.
Bill described the four different viruses associated with little cherry disease new isolate similar to the German one, now causing problems in the U.S. Other viruses they are seeing include cherry rusty mottle foveavirus, another foveavirus causing pitting on montmorency interstock, and a third foveavirus just being characterized.
Peach latent mosaic viroid update: peach blotch disease (?) may be PLMVd severe strain (mild strains dont cause symptoms). Lauri ran a CAPS project to test all mother trees, peach and nectarine 50% had PLMVd. Will repeat in a few years, to see if flushing system with clean material works to start cleaning this up.
Apple green crinkle disease is getting to be a big problem. Only expressed in fruit during years with prolonged, cool Spring. Causal agent not clear, probably because it is a multi-component complex. Bill did differential heat treatments on green crinkle wood, to try to separate out agents. This year was first year with fruit. One tree showing symptoms has no ACLSV, which was their prime suspect originally.
ACLSV associated diseases in Prunus are more common these days prune plums, incompatibility in cherry, brown line, gumming on trunks, brown streaks.
Lauri described disease findings in certified mother blocks. Bill mentioned the new paper that addresses economic impact of clean stock programs. He also mentioned a new grape foundation program for WA, OR, ID, BC at WSU station.
John Hu, WCC20 chair for 2003, thanked all the presenters and participants (about 30 people), and made some closing remarks.
Dan Thompson, CFIA Centre for Plant Health, Sydney, B.C. During the NE1006 portion of the meeting, Dan presented an update on host range studies for the Canadian isolates of PPV. During WCC20, he reported on work to optimize a system for detection of fruit tree phytoplasmas by PCR, utilizing the same RNA extraction also used for virus PCR tests. Dan found the test fairly reliable from early June through October, using either RNA or DNA extraction.
Roberto Michelutti, Agriculture and Agri-Food Canada Clonal Genebank, Harrow, Ontario, reported on testing for viruses in Fragaria, Rubus, Malus, Pyrus, and Prunus in their collection. Two years of plum pox screening have yielded all negative results. In collaboration with colleagues in Spain and Italy, Roberto used a tissue printing assay for PLMVd, hop stunt viroid, and PPV.
Deborah Golino, Foundation Plant Services, UC-Davis, showed work on experimental transmission of two closteroviruses (grapevine leafroll-associated Virus 5 and 9) by Longtailed Mealybugs. She discussed the complexity of the system and the difficulty in identifying singlely-infected plants. She also mentioned that a relatively new mealybug species to CA (the vine mealybug) is changing the dynamics of the system.
Jerry Uyemoto, USDA-ARS, UC-Davis gave an update on the rootstock genotypes that react with Redglobe virus (GLRaV-2 RG). The virus kills five rootstocks within two dormancy periods. Jerry recommends that, to properly monitor for virus disease agents, numbers of biological indicators should increase rather than decrease.
In tree fruits, Jerry showed three separate instances of the occurrence of Cherry Virus A in CA, each in combination with other viruses and with different symptoms. He also described a Bing cherry with cherry necrotic rusty mottle foveavirus, and graft-transmissible Plum Bark Necrosis Stem Pitting on black beaut.
John Hu, from the University of Hawaii, presented his work on survey and control of Citrus Tristeza Virus (CTV) in Hawaii. CTV isolates have been collected and characterized at the serological and molecular level. Significant strain diversity exists in Hawaii: variation within and between groups is 91% with HI and foreign alignments, even excluding outliers from the analysis. Development of transgenic plants with broad resistance is a current goal, using a chimeric transgene approach in the Mexican Lime regeneration system. Johns group is also evaluating local CTV strains as cross protection candidates, and has identified several promising mild isolates.
Harold Larsen, Colorado, discussed local industry changes the apple industry is shrinking in size; peach now #1, apple #2, wine grape #3 in acreage. Harold is now 65% viticultural support powdery mildew in grape and bloom delay in grapes. Increasing interest in sweet cherries. Have cherry raspleaf (in peach, cherry, apples). Would like to see development of rootstocks with resistance to CRLV acquisition. Harold showed images of grape displaying a necrotic vein symptom of unknown etiology, as well as some suspected chemical injury and other pests in grape. Peach mosaic and peach wart have not been seen in recent years.
Ray Mock, USDA-ARS Plant Germplasm Quarantine Office, Maryland, described administrative changes in their unit, staffing shortages, and an update on their building project. This year, imports received were very near their maximum capacity, and many releases were made, with a large number of samples still in process in therapy and testing via standard regimen. The unit intercepted disease agents in pome fruits, stone fruits, and small fruit.
The molecular research lab, under the guidance of Dr. Li, is developing new methods for testing, currently working with CGRMV and CNRMV in Prunus, blackcurrant reversion and gooseberry vein banding virus in Ribes.
Ruhui Li USDA-ARS Plant Germplasm Quarantine molecular research lab, Maryland, provided a research report on detection of cherry green ring mottle and cherry necrotic rusty mottle foveavirus by rt-pcr. The original objective of the research was to investigate replacement of biological assay with pcr. Using sequences from both viruses, Dr. Li developed consensus primer sequences for the two viruses, and developed a fast, simple, and reliable RNA prep method.
Ramon Jordan, USDA-ARS, Beltsville, Maryland, mentioned that he was working to identify potyviruses that react in the Durviz PPV ELISA test. Preliminary evidence points to a Tulip-breaking-like virus in lily, tested originally by John Halbrendt in Pennsylvania, that cross-reacts.
Annemiek Schilder, Michigan State Univ., reported on fruit virology activities in Michigan. Annemiek provides diagnostic support for small fruit growers. Blueberry disease symptoms have increased in 2003: shoestring predominant, with some tobacco ringspot, stunt suspected but not confirmed, and virus-like symptoms cold injury in blueberries, potato leafhopper in raspberries. Tobacco ringspot finds in table grape planting stock initiated a program of screening mother blocks and propagating virus-free planting material. Virus-free blueberry nursery program is also available and expanding.
Annemiek summarized MI Dept. of Agriculture program testing pome and stone fruit nursery stock, a Michigan breeding program for virus tolerance in sweet cherries, a research program on virus-mediated resistance in cherries, work with the blueberry red ringspot promoter as an alternative to CaMV 35S, and development of a new IPM scouting guide for grape.
Gene Milbrath, OR Department of Agriculture, summarized work in Bob Martins lab, Corvallis. All blueberry coming into state must be tested for blueberry scorch, in an effort to prevent more aggressive strains from becoming established. Bob is investigating possibility of blueberry scorch in cranberries. He is also working with whitefly-transmitted viruses in small fruits blackberry yellow vein-associated virus appears to have been distributed across southeast from Arkansas breeding program, beet pseudo-yellows virus in blackberries from southeast and in strawberries from CA and MD. Aphid-borne viruses in strawberry from NW cause severe decline in one variety of strawberry that was developed as a tolerant variety.
ODA plum pox survey has concentrated in orchards around nurseries, rather than nurseries themselves, in 2003; did special pumiselect sampling as part of traceback work for a positive in PA. All PPV testing of Oregon material negative. 26 nurseries in certification testing for ilars and ToRSV. Becoming a large ornamentals program with fruit trees declining. Did do cherry leafroll survey in Oregon cherry orchards. Some suspicious symptoms, but all tested negative.
Simon Scott, Clemson University, South Carolina, gave a status report on work with Ta Tao varieties and their associated viruses and viroids. He is attempting to tease out the components of the system that result in bloom delay in Ta Tao and related Chinese genetic resources. So far, various combinations of Asian Prunus Latent Virus, perhaps several other foveaviruses, peach latent mosaic viroid, and apple chlorotic leafspot virus have been implicated. Simon is also experimenting with Okinawa rootstock as an indicator plant for various Prunus viruses. During NE1006 portion of meetings, Simon also presented information on PPV sampling and testing of fruit all negative.
John Halbrendt, Pennsylvania State University, and Ruth Welliver, PA Dept. of Agriculture, both presented information on 2003 PA plum pox work during the NE1006 portion of the meeting. In addition, they mentioned an apple decline situation they are investigating.
Bill Howell, NRSP5, Washington state (with input from Laurri Guerra, WA Dept. of Agriculture), discussed the emergence of Cherry Leafroll Virus decline disease in sweet cherry. Disease can be even more severe in mixed infection with ilarviruses. Washington state fruit commission worked to clean up orchards through educational/survey program involving extension, fruit packing warehouse fieldmen, and growers. Removing diseased trees must use herbicide to detect root grafts (see herbicide damage the next spring), and insecticide to kill vectors before removing trees in summer time.
Bill described the four different viruses associated with little cherry disease new isolate similar to the German one, now causing problems in the U.S. Other viruses they are seeing include cherry rusty mottle foveavirus, another foveavirus causing pitting on montmorency interstock, and a third foveavirus just being characterized.
Peach latent mosaic viroid update: peach blotch disease (?) may be PLMVd severe strain (mild strains dont cause symptoms). Lauri ran a CAPS project to test all mother trees, peach and nectarine 50% had PLMVd. Will repeat in a few years, to see if flushing system with clean material works to start cleaning this up.
Apple green crinkle disease is getting to be a big problem. Only expressed in fruit during years with prolonged, cool Spring. Causal agent not clear, probably because it is a multi-component complex. Bill did differential heat treatments on green crinkle wood, to try to separate out agents. This year was first year with fruit. One tree showing symptoms has no ACLSV, which was their prime suspect originally.
ACLSV associated diseases in Prunus are more common these days prune plums, incompatibility in cherry, brown line, gumming on trunks, brown streaks.
Lauri described disease findings in certified mother blocks. Bill mentioned the new paper that addresses economic impact of clean stock programs. He also mentioned a new grape foundation program for WA, OR, ID, BC at WSU station.
John Hu, WCC20 chair for 2003, thanked all the presenters and participants (about 30 people), and made some closing remarks.
Impacts
- Much of the research of WCC20 participants, facilitated by interaction at WCC20 meetings, is immediately and directly applied to improve clean stock programs or to justify establishment of new clean stock programs.
- The economic impacts of clean stock programs on plant propagators, fruit growers, and consumers was recently quantified, amounting to over $200 million annually.
- Efforts of the group to improve detection and elimination of viruses and virus-like agents entering the continent on infected plant material will result in savings to pest detection and control programs (such as the $40 million plum pox eradication program ongoing in Pennsylvania).
- Impacts of transgenic resistance development is also easily seen in the success of the transgenic papaya work, bringing new life to Hawaiis papaya industry, and now being applied to systems such as citrus tristeza and plum pox virus.
Publications
Cembali, T., R.J. Folwell, P. Wandschneider, K.C. Eastwell, and W.E. Howell. 2003. Economic implications of a virus prevention program in deciduous tree fruits in the US. Crop protection 22:1149-1156.
Marini, D. B., Rowhani, A., and Uyemoto J. K. Discovery of a new graft-transmissible agent causing bark necrosis and stem pitting in ‘Black Beaut‘ plum and symptoms in other Prunus species and varieties. California Agriculture 56(3):108-111. 2002.
Uyemoto, J. K., Buylluck, III, L. R., Pethybridge, Sarah, McCorkell, Bruce, and Asai, W. K. Horizontal spread of ilarviruses in young trees of several peach cultivars. Plant Dis. 86:75-77. 2003.
Marini, D. B., Rowhani, A., and Uyemoto J. K. Discovery of a new graft-transmissible agent causing bark necrosis and stem pitting in ‘Black Beaut‘ plum and symptoms in other Prunus species and varieties. California Agriculture 56(3):108-111. 2002.
Uyemoto, J. K., Buylluck, III, L. R., Pethybridge, Sarah, McCorkell, Bruce, and Asai, W. K. Horizontal spread of ilarviruses in young trees of several peach cultivars. Plant Dis. 86:75-77. 2003.