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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #238369

Title: Grapevine Fanleaf Disease in Washington State Vineyards

Author
item MEKURIA, T - Washington State University
item GUTHA, L - Washington State University
item Martin, Robert
item NAIDU, R - Washington State University

Submitted to: Washington Association of Wine Grape Growers Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/24/2009
Publication Date: 4/5/2009
Citation: Mekuria, T., Gutha, L.R., Martin, R.R., Naidu, R.A. 2009. Grapevine fanleaf disease in Washington State vineyards. Washington Association of Wine Grape Growers Annual Meeting.

Interpretive Summary:

Technical Abstract: Wine grapes (Vitis vinifera L.) are susceptible to a wide range of viruses. Among them, grapevine degeneration caused by Grapevine fanleaf virus (GFLV) is considered as one of the most economically important virus diseases affecting grapevines worldwide. Infected grapevines show a range of foliar symptoms consisting of leaf deformation, yellow mosaic, vein banding, ring and line patterns and flecks. GFLV cause yield reductions as high as 80% depending on the cultivar and severity of infection. Plant-to-plant spread of GFLV is known to occur by dagger nematode (Xiphinema index), and hence the infected grapevines appear in patches in the field. Long distance spread of the virus, however, occurs by distribution of infected propagation material. GFLV has been documented in grapevines in different viticultural regions of the United States. But the occurrence of GFLV in the Pacific Northwest was not documented until 2008. While testing wine grape cultivars for the presence of different Grapevine leafroll-associated viruses (GLRaVs), we detected GFLV in four different wine grape cultivars, Pinot Noir, Cabernet Franc, Merlot and Chardonnay, from geographically widely separated vineyards. The presence of GFLV in these cultivars was further confirmed by molecular analysis of DNA fragments amplified by reverse transcription-polymerase chain reaction (RT-PCR). The results also showed GFLV occurring as mixed infection with other grapevine viruses. Molecular analysis of GFLV genomic fragments revealed that the virus occurs as genetically diverse isolates in Washington State vineyards. Studies conducted to determine the spatial distribution of fanleaf disease in Chardonnay block indicated random distribution of GFLV-infected vines suggesting that the virus was possibly introduced through infected cuttings. Soil samples from GFLV infected Chardonnay block contained the nematode Xiphinema pachtaicum, but GFLV was not detected in these nematodes. Anecdotal evidence based on discussions with concerned growers suggested that GFLV was possibly introduced through virus-infected cuttings.