Brief Summary of Minutes of Annual Meeting

WCC-20 Minutes
June 11-13, 2001
Appalachian Fruit Research Station
Kearneysville, WV


The meeting began with introductions by WCC-20 2001 meeting coordinator Gary Kinard (USDA ARS) and welcome from Appalachian Fruit Research Station (AFRS) Research Leader Dariusz Swietlik. There were 31 in attendance (listed at end).

Discussions were held regarding the site for 2002 meeting. John Hu (University of Hawaii) volunteered to be local coordinator with the meeting held in Hawaii. Motion voted on and passed.

The death of Merritt Nelson was announced. A sympathy card was circulated to be sent to Nelson‘s family. A scholarship is being established in Nelson‘s honor. Also, George Nyland deceased in 2001. He was a founding member of WCC-20.

Ralph Cavalieri of Washington State University is the new administrative advisor to WCC-20. The WCC-20 is up for review, Ken Eastwell has written the proposal for the group‘s renewal. This will be voted on by Western research station directors. Ken has copies of the project re-write. Thanks to Ken for his efforts.

Bill Howell (Washington State University) asked to initiate a discussion of issues of impact on fruit tree stock imports by free trade agreements (FTAs). FTAs are changing the way pests are prevented from entering the country. Rules imposed on importers must be the same as rules for exchange within our country. For fruit trees and grapevines we will have to open our borders or impose mandatory certification programs for internal trade in the nursery industry. Bill has been asked by the northwest nursery industry to draft certification programs. One example of the current state of affairs is in California where 90% of free stone peaches are not virus certified. Bill mentioned the need to work with breeders to establish a paper trail for virus certification of new varieties.

Deborah Golino (University of California, Davis) continued the discussion noting that there are mandatory national certification programs in place in other countries. In the US we have the highest standard in the world with strict quarantine combined with extension and research programs. This high standard for voluntary programs works, but is not in keeping with international law. The North American Plant Protection organization (NAPPO) is working with Canada and Mexico on this. The US is still not prepared to go to the international community because we have no mandatory programs in place. She referred the group to an article by Joseph Foster on this subject.

Simon Scott (Clemson University) noted that plum pox virus (PPV) has revealed problems with the system in the Southeastern US. Ruth Welliver (Pennsylvania Department of Agriculture) added current practices do not encourage vigilance about maintaining an adequate paper trail for nursery stock. Growers are concerned about mandatory controls impinging on their freedom to propagate and trade stock. She mentioned a need for increased education in years when crises are not occurring to keep these problems at the front of their minds.

Joseph Postman (USDA APHIS) raised the question of strict controls limiting the availability of minor cultivars.

Gene Milbrath (Oregon Department of Agriculture) noted recent movement of ornamental Prunus has led to much interest in voluntary programs.

Ray Johnson (Agriculture Canada) mentioned that NAPPO is coordinating import and phytosanitary issues with between Canada, the US, and Mexico. NAPPO is looking to establish common standards. Five years ago rules were established for grapes. They are still working on standards using a very short list of pathogens. These standards are available on the NAPPO website.

State Reports:

Deborah Golino (UC Davis) reported on efforts to identify causes of sudden increase in severity and frequency of virus disease symptoms in grapevines in California vineyards. She hypothesized that some of the increase may have been due to shifts in rootstock planting preferences. Studies were undertaken to determine whether the decline of these vineyards was associated with virus infection, which viruses are involved, and to quantify the effects on these viruses on various rootstocks.

Jerry Uyemoto (USDA ARS) reported detection of new graft-transmissible agents associated with grape rootstock stem lesion disease, and efforts to isolate and clone the causal agent of plum bark necrosis-stem pitting disease.

Harold Larsen (Colorado State University) reported a new disorder called peach wart. Indexing tests are being performed by NRSP-5. Other projects involve peach latent mosaic viroid, peach mosaic, cherry rasp leaf virus, and phytoplasma.

Ray Johnson (Agriculture Canada) gave an update on PPV found in southern Ontario and Nova Scotia. The same strain "D" type as the Pennsylvania isolates was identified. The Nova Scotia block was eradicated. Ontario has responded with quarantine in certain areas and block removal in other sites.

John Hu (University of Hawaii) reported on an interesting etiological phenomenon in mealy bug wilt of pineapple. Plants infected with the virus alone show no symptoms and plants infested with mealy bugs but not infected with virus show no symptoms. The mealy bugs apparently inject some compound that makes the plant more susceptible to the virus.

Sarbagh Salih (USDA ARS) gave an overview of the in vivo and in vitro therapy programs at the Plant Germplasm Quarantine Office (PGQO) in Beltsville MD. She outlined the time line for pome fruit therapy and gave a status report on future plans for therapy on Prunus.

Ray Mock (USDA ARS) reviewed activities at PGQO including statistics on introductions and releases of the various small and tree fruit crops quarantined at Beltsville, as well as progress on building of the new facility there.

Laurene Levy (USDA APHIS) is the acting director of the Plant Protection and Quarantine PPQ station at Beltsville. She reported on use of new technology for rapid in-field testing. She gave an account of some of the budget issues PPQ is facing with the new administration.

Joseph Foster (USDA APHIS) discussed some problems and definitions involved in international trade of germplasm. He noted the perception of disparity resulting when we impose voluntary internal controls but require restrictions on imported germplasm.

Joseph Postman (USDA ARS) presented an overview of the pear and other collections at the National Clonal Germplasm Repository in Corvallis OR. Highlights included pear blister canker viroid association with severe stony pit isolates, gooseberry vein banding virus found in other Ribes crops, and his research at the National Agricultural Library on their collection of 7000 pomological watercolors from the 19th century, documenting a diversity of fruit crop varieties.

Gene Milbrath (Oregon Department of Agriculture) reported on blueberry scorch virus. Very little resistance in commercial cultivars. Concerns with increased acreage of blueberries, lack of certified stock. A pest alert for blueberry scorch is on their website www.odu.state.or.us

Ruth Welliver (PA Dept of Agriculture) reviewed PPV monitoring and containment activities in Pennsylvania and the economics and politics of eradication. Some statistics: 18 positive blocks in 1999. 40 in 2001. 1159 acres destroyed to date. Cost of effort so far $30 million.

Simon Scott (Clemson University) told about his efforts to work with the nursery industry in the Southeastern US on virus certification programs and some of the challenges encountered in changing the attitudes of an industry still using questionable practices in the trade, increase and marketing of nursery stock.

Ken Eastwell (WSU) reported a virus-induced decline of sweet cherry associated with cherry leaf roll virus. Not sure of transmission. It is a nepovirus but no nematode vector identified. Also looking at cause of green crinkle. He reported on a grapevine virus survey to get a baseline of viral infections in Washington vineyards and isolation of a carlavirus associated with black death disease of Helleborus that was transmitted to other hosts with green peach aphids.

Bill Howell (WSU) reviewed work on an ilarvirus of cherry, prunus dwarf virus. Some new cherry rootstocks are sensitive to PDV and PNRSV. A survey found varying degrees of sensitivity to PDV and PNRSV. He also reported an association of green crinkle in apple with ACLSV, ASPV and ASGV.

Roberto Michelutti (Ag Canada) reported on his work indexing the Canadian clonal germplasm repository in Harrow.

Vern Damsteegt (USDA ARS) presented highlights of his work on PPV. He noted that the strain D is actually a serogroup with some variation within the D epitope. He has PPV strain D in an herbaceous host and is working on producing antisera. He noted striking patterns of chlorosis and necrosis on P. tomentosa. He mentioned some differences between the European strain D and the Pennsylvania strain D such as production of lesions in quinoa. He also mentioned seedlings taken from PPV infected orchards showing mosaic symptoms but without finding any pathogens. The agent is graft transmissible.

Zvezdana Pesic-Vanesbroeck (NC State University) gave an overview of NC State‘s indexing and micropropagation program for sweetpotato and strawberry.

Dariusz Swietlik gave an overview of activities at AFRS including mechanical harvest technology, particle films and sugar esters for crop protection, natural product chemistry to combat forborne pathogens, transgenic and traditional breeding programs, new selection, and horticultural methods development.

The group toured AFRS on July 12 and went on a field trip to Chrysalis Vineyards in Middleburg Virginia and to two PPV sites in Adams County Pennsylvania on July 13. Tony Wolf (Virginia Polytechnic Institute) gave a presentation on grapevine yellows phytoplasma at Chrysalis Vineyards. The group then traveled to Adams County Pennsylvania where Ruth Welliver arranged for the group to examine PPV symptoms on trees at two commercial orchards.