Brief Summary of Minutes of Annual Meeting

The meeting was called to order at 8:15. Minutes of the 2003 meeting were approved unanimously. Adib Rowhani was acknowledged for the great job of organizing the WCC-020 meeting and agricultural tour, and for making local arrangements for the NRSP5 meeting. Eastwell reported the impact of the USDA-ARS research enhancement. With the addition of a Post-Doctoral position at USDA-ARS working with our project, we have made progress in developing diagnostics for several virus diseases of cherry. The primary subjects are those that have been difficult to detect and including the viruses that cause little cherry disease, and the viruses of the family Foveavirus. It was reported by Woodson that the North East, South and Western Regions had approved the NRSP5 budget request at the 2004 funding level. The North Central region had recommended decreasing budgets of FY05 $200,000; FY06 $100,000; FY07 $0. The timeline for consideration of the budget request was discussed. The guests joined the meeting. Dr. Golino described the funding for FPS in detail for both the grape and tree fruit program. The concept of a national network of virus-tested stock of perennial crops was presented. This would coordinate with local and regional agencies already doing some activities. The parallel in the research and service activities of many horticultural crops was discussed. It is evident that there is an opportunity to coordinate these activities in a very effective manner. The possibility of encompassing all horticultural crops was considered. It was generally agreed that a program that encompassed all horticultural crops would be difficult to coordinate early in the development of a clean stock network. There was already a natural alliance between fruit tree, nut trees and grapevines. It was unanimously decided to pursue a national program encompassing these latter commodities. The network would be structured such that additional crops could be added at later dates, providing additional funding was made available. Eastwell and Golino agreed to take the initial steps for developing a coordinated drive to establish such a network and to elicit Bewick's assistance at CSREES. The meeting was adjourned at 4:30

BRIEF SUMMARY OF PROJECT ACCOMPLISHMENTS FOR THE PAST CALENDAR YEAR. NRSP5 Activities-2003 - 04 Improved diagnostics: Production of molecular and serological probes: The causal agents of many virus diseases of pome and stone fruit trees have never been identified. Characteristics of woody plants made it very difficult for scientists to work on these virus and virus-like agents. However, with the advent of improved molecular techniques, the nature of many of these disease agents is now being studied. In the past year, we identified the causal agents of cherry rusty mottle disease and a stem pitting disorder of Montmorency cherry trees as members of the Foveavirus family. Using sequence information developed in our project, an ELISA has been used to successfully identify the agent causing the Montmorency cherry stem pitting disorder, and this has been applied in the field to try to minimize the spread of this disease. The production of serological reagents for other Foveaviruses is in progress. We compared ELISA reagents and PCR reagents from several sources and established a reliable testing protocol for detection of a broad spectrum of Apple chlorotic leafspot virus isolates. Prior to 2001, certified fruit trees from US nurseries were permitted into Mexico on a provisional basis, that is, the shipment was allowed to pass but samples were taken at the port of entry for virus testing. In 2001, audit samples of Malus rootstock yielded positive results for Apple chlorotic leafspot virus; we confirmed that the test results from the Mexican laboratory were correct. In response to discovering virus in these earlier shipments, trees imported into Mexico in 2002/2003 were held at the border until spot checks could be completed. The delay resulted in 80% tree mortality. To avoid a repeat, we hosted a visit by Dr. Ramiro Gonzalez Garza and negotiated an appropriate validation procedure. We performed tests on samples of cherry and apple collected by Mexican officials from OR and CA nurseries, and we developed protocols for testing 5 viruses and phytoplasmas for apple and 10 for cherry. Dr. Garza visited our laboratories and examined our protocols and results in February 2004. We also conducted comparative tests with the Mexican laboratory. Because of these efforts, results of the certification programs (based on our protocols) are now accepted by the Mexican government and material from certification nurseries can again be shipped to Mexico with minimal delays at the international border. The Mexican market currently constitutes a significant percentage of the business conducted by US nurseries. In a cooperative project funded through USDA-ARS, we are looking at the development of reagents and techniques for the detection of the viruses associated with little cherry disease. To date, we have serological reagents for Little cherry virus-2, but the detection of Little cherry virus-1 has been problematic. The North American isolate(s) of the latter virus appears to be significantly different from the isolate reported in Europe. We have one USDA-ARS funded Post Doctoral scientist working on this project with Washington State University researchers. Apple green crinkle etiology: Apple green crinkle disease is another disease for which the causal agent is unknown. A complicating factor in studies with this disease is that all known infected plants contain three common viruses and possibly others. Separation of these various components in etiological studies is difficult. Over the past several years we have worked to separate the many viruses of this complex by propagating shoot-tips of diseased trees following heat treatment for various periods of time. Trees thus created were established in an orchard. Most trees are now bearing fruit which will allow us establish a correlation between virus-like agents present in the initial complex and the occurrence of green crinkle disease. Cherry stem pitting etiology: In a cooperative project with Dr. Jerry Uyemoto, USDA-ARS and Dr. Joe Grant, UC-Davis, Cooperative Extension, studies to determine the etiological agent that causes cherry stem pitting disease are underway. This disease has been recognized as serious problem in limited areas of California fruit production for several years, and now appears to occur in other States. Other research and virus management activities: Cherry leaf roll virus: A cherry leaf roll virus disease survey and eradication program conducted in partnership with the Washington Tree Fruit Research Commission, Washington State Cooperative Extension, and Washington State University brought grower attention to this malady. Initiated in 2003, growers, fieldsmen, and crew foremen learned to identify the symptoms and to send samples to the WSU-ELISA lab for verification. Most, if not all, identified trees were removed before the 2004 growing season. A few newly infected trees were observed this spring in trees adjacent to previously diseased sites. However, observations this spring suggest that growers were highly successful in efforts to eliminate this virus from their orchards. We did field surveys in the central valley of California, supported by laboratory tests, to see if there had been any natural movement of the walnut isolates of Cherry leafroll virus into adjacent sweet cherry plantings. This work was conducted in cooperation with Dr. Jerry Uyemoto, USDA-ARS and Dr. Joe Grant, UC Cooperative Extension, Stockton, CA. Virus Effects: In research orchards that were established several years ago, we continue to evaluate the effect of latent apple viruses on fruit production and quality of 'Fuji' apple trees. Similarly, the effects of Peach latent mosaic viroid on one nectarine and five peach cultivars are being monitored. Standards for the movement of temperate fruit trees: NRSP5 personnel have been active participants on committees associated with the North American Plant Protection Organization and the National Plant Board in efforts to establish standards for reducing risk of transporting pests in shipments of deciduous fruit trees. Variety distribution and acquisition: NRSP5 was active again this year in distributing virus-tested budwood for research and for production of certified trees. During the past nine months, small lots totaling over 20,000 buds were sent to scientists, state certification agencies, nurseries, and growers. Other requested materials included pollen for breeding programs and healthy and diseased cuttings, fruit, leaves, etc. for studies on disease etiology, molecular identification of varieties, and propagation experiments. Seed, seedlings, and trees from virus-tested sources were also distributed when requested. Forty-five new selections were imported from foreign countries for virus testing and therapy at NRSP5 this past year, as were 66 proprietary and non-proprietary clones from domestic sources. Virus was detected in 15 percent of the imported pome fruit clones; most of those were from China. Selections from breeding programs in New Zealand were generally free of detectable virus. Six percent of the introduced stone fruit selections contained either PNRSV or Prune dwarf Ilarvirus (PDV). Program funding restructuring: An initiative to create a National Clean Plant Network was developed that would see the coalescence of several fruit tree, grapevine and nut tree programs into a system of facilities to enhance the production and distribution of virus-tested material throughout the U.S.A. This would result in a more efficient and robust system of distribution for virus-tested material, and its availability to the nursery industry. If adopted, this could serve as a model for other crops.