SAES-422 Multistate Research Activity Accomplishments Report

Sections

Basic Information
Additional Info

Status: Approved

Basic Information

Project No. and Title: WERA_OLD20 : Virus and virus like diseases of fruit trees, small fruits and grapevines
Period Covered: 06/01/2004 to 05/01/2005
Date of Report: 08/22/2005
Annual Meeting Dates: 05/16/2005 to 05/18/2005

Ralph Cavalieri, Washington State University, Pullman, WA; Ken Eastwell, Washington State University, Prosser, WA; Raymond G. Mock USDA, ARS, Fruit Laboratory, Plant Germplasm Quarantine Office; Lauri Guerra, Washington Department of Agriculture, Prosser, WA; Mary Horner, HortResearch, New Zealand; Bill Howell, Washington State University, Prosser, WA; John Hu, University of Hawaii, Oahu, HI; Roberto Michelutti, Ag-Canada, Harrow, Ontario; Adib Rowhani, FPS/UC-Davis, Davis, CA; Simon Scott, Clemson University, Clemson, SC; Dan Thompson, CFIA, Sidney, British Columbia; Mike Tiffany, Agdia, Inc., Elkhart, IN; Zvezdana Pesic-Vanesbroeck, NC State University, Raleigh, NC

Brief Summary of Minutes of Annual Meeting

Please see attached file to include information on the following: Virus and virus like diseases of fruit trees, small fruits and grapevines 2005 Annual Meeting - Minutes JC Raulston Arboretum, NCSU, Raleigh, NC May 16-18, 2005 I. Opening Remarks; II. State Reports; III. Business meeting; IV. Other activities In addition to the 2005 Report for the WCC 20 Meeting titled: USDA-ARS Fruit laboratory Plant Germplasm Quarantine Office Pome, Stone, Small Fruit, and Molecular Diagnostic Programs Beltsville, MD May 16-18, 2005

Legacy attachment file:

[Minutes]

Accomplishments

Repeated vegetative propagation of sweet potatoes had resulted in the accumulation of viruses with resulting declining production after 7 years, and resulting loss of market share. Similarly, bacterial and fungal diseases of strawberry introduced from outside of NC impeded production. A micropropagation unit was established at North Carolina State University to produce virus-tested material for sweet potato and strawberry propagation. Plant Germplasm Quarantine Office of USDA-ARS and the National Research Support Project 5 have major beneficial impacts on the production objectives for stone, pome, and small fruits in the United States by providing virus-tested material to researchers and to industry. Virus detection methods are being enhanced through the cooperative efforts of several researchers associated with WERA-020, such as the recent development of a robust molecular assay for a virus associated with grapevine leafroll disease, but escaped detection by other serological or RT-PCR detection methods. A Southeast Budwood Program has been created that is supported by South Carolina, Georgia and three major nurseries in Tennessee. This certification program was initiated in 2000 in response to concerns about Plum pox virus (PPV), but all trees in this program are now tested PPV, as well as the Ilarviruses that contribute to early loss of production in peach orchards. A research and observation program for developing and monitoring Citrus tristeza disease resistance in citrus has been established in Hawaii. An industry sponsored program was launched in Washington State to detect and remove cherry trees infected with Cherry leafroll virus. The survey was funded by industry and operated through the chemical and fruit packing houses to optimize the use of individuals that are frequently in the orchards. The survey was accompanied by an intense educational program to increase the awareness to viruses and their negative impact on production. In 2004 the Canadian Plum pox virus (PPV) eradication program was given an $85 million seven year extension. The program is based on finding and removing all the PPV infected trees and replanting with clean trees. Cherry rasp leaf virus is one of the most prevalent fruit viruses in Colorado. Cherry rasp leaf virus infections continue to appear in newer sweet cherry blocks around age 6-10 years. However, sweet cherry acreage is below 300 acres for the state and production value likely is less than $150,000. Growers have found that plantings on Colt rootstock typically don't begin to exhibit symptoms until around year 9 or 10 or sometimes later, while plantings on other rootstocks begin to show symptoms around year 4 -6. There is interest among growers to look at cherry rootstock and interstem combinations to assess CRLV resistance for sweet cherries. Tentative plans have been made for next spring to initiate a greenhouse pot trial using Bing / Z-interstem / Citation RS trees (to be provided by Dave Wilson Nursery).

Impacts

Currently, 45,000 acres of sweet potato valued at $60M are planted with material derived from the NCSU certification program.
The strawberry program at NCSU develops plants that are transferred to certified nurseries that are required to grow certified material only, and from here, the plants are distributed throughout the southeast.
An effective quarantine program encourages compliance with federal regulations regarding movement of germplasm and diminishes the temptations to smuggle plant material into the United States.
Therapeutic methods to eliminate pathogens can salvage potentially valuable germplasm.
Improved detection methods for quarantine pathogens can reduce the time germplasm is held in quarantine, as well as improve the reliability of the testing programs.
Quarantine programs intercept new or emerging pathogens or strains/isolates of a pathogen that may threaten US agricultural security.
The Southeast Budwood Program currently includes 40-50 varieties of commercial interest, most of which are unique to southeast peach production.
From a national perspective, Hawaii is in a unique position to develop and test control strategies for CTV. Such control strategies would not only be beneficial to Hawaii`s citrus industry, but also other citrus-producing regions that are threatened by CTV and the BrCA.
Cherry leafroll virus is a destructive virus of sweet cherry trees and has recently been detected in the Northwestern US fruit production areas. The extent of disease spread has been delineated and many infected trees have been removed. In response to this program, some County agencies also established and funded virus control programs.
A database of plant species that are susceptible to Plum pox virus is being developed. Knowledge of which plant species are hosts of PPV is critical to accomplish this goal.

Publications

Thompson D. 2005. Practical Applications of the Plum Pox Virus Standard. NAPPO Newsletter, June, 2005. Ian McDonnell ed. North American Plant Protection Organization. Alkowni R, Rowhani A, Daubert S, Golino D. 2004. Partial characterization of a new ampelovirus associated with grapevine leafroll disease. J. Plant Pathol. 86:123-133. Newman K, Almeida RPP, Purcell AH, Lindow S. 2004. Cell-cell signaling controls Xylella fastidiosa interactions with both plants and insects. Proc. Nat. Acad. Sci. 101:1737-1742. Almeida RPP, Mann R, Purcell AH. 2004. Xylella fastidiosa cultivation on a minimal defined medium. Curr. Microbiol. 48:368-372. Purcell AH, Okano K. 2004. Effects of sublethal doses of imidacloprid on vector transmission of Xylella fastidiosa. Pages 146-149 in Proceedings of Pierce's Disease Research Symposium, Coronado, CA, Dec. 7-10, 2004. Purcell AH, Curley CM. 2004. Effects of chemical milieu on attachment, aggregation, biofilm formation, and vector transmission of Xylella fastidiosa strains. Pages 224-226 in Proceedings of Pierce's Disease Research Symposium, Coronado, CA, Dec. 7-10, 2004. Purcell AH, Almeida RPP. 2004. Role of bacterial attachment in transmission of Xylella fastidiosa by the glassy-winged sharpshooter, and other factors affecting transmission efficiency. Pages 227-230 in Proceedings of Pierce's Disease Research Symposium, Coronado, CA, Dec. 7-10, 2004. Purcell AH, Lindow S, Baccari C. 2004. A screen for Xylella fastidiosa genes involved in transmission by insect vectors. Pages 231-233 in Proceedings of Pierce's Disease Research Symposium, Coronado, CA, Dec. 7-10, 2004. Purcell AH, Lindow S, Wistrom C. 2004. Patterns of Xylella fastidiosa infection in plants and effects on acquisition by insect vectors. Pages 234-237 in Proceedings of Pierce's Disease Research Symposium, Coronado, CA, Dec. 7-10, 2004. Almeida RPP, Wistrom C, Hill BL, Hashim J, Purcell AH. 2005. Transmission of Xylella fastidiosa to dormant grapevines. Plant Dis. 89:419-424. Publications in Press (proofs returned) Wistrom C, Purcell AH. 2005. The fate of Xylella fastidiosa in vineyard weeds and other alternate hosts in California. Plant Dis. 89:[in press 6-05] Almeida RPP, Purcell AH. 2005. Vector transmission of Xylella fastidiosa: applying fundamental knowledge to generate disease management strategies. Ann. Entomol. Soc. Am. [in press 6-05] Bressan A, Purcell AH. 2005. Effect of benzothiadiazole on transmission of X-disease phytoplasma by the vector Colladonus montanus to Arabidopsis thaliana, a new experimental host plant. Plant Dis. 89:[in press 7-05]

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