Submitted to: American Journal of Enology and Viticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2013
Publication Date: 12/1/2012
Citation: Zasada, I.A., Riga, E., Pinkerton, J.N., Wilson, J.H., Schreiner, R.P. 2012. Plant-parasitic nematodes associated with grapevines, Vitis vinifera, in Washington and Idaho. American Journal of Enology and Viticulture. 63:522-528. Interpretive Summary: Plant-parasitic nematodes are microscopic roundworms that have been shown to cause significant yield loss in grapevines worldwide. Washington and Idaho both have growing wine grape industries, with eastern Washington being the second largest grape producing region in the United States. Despite the fact that plant-parasitic nematodes are important parasites of grapevines, no information is available on the occurrence and distribution of these organisms in Washington and Idaho vineyards. This research was conducted to determine which plant-parasitic nematodes are associated with grapevines in this region, and to relate the occurrence of nematodes to specific vineyard site characteristics and management practices. Soil samples were collected from 197 vineyards and nematodes were extracted, counted, and identified from these samples. Root-knot and dagger nematodes were detected in more than 50% of surveyed vineyards in Washington and Idaho, while root lesion, pin, and spiral nematodes were also commonly encountered in Idaho vineyards. Differences in the types and numbers of plant-parasitic nematodes were found among geographical areas and grape types (red, white, and juice grapes). These results are significant because they are the first to document the occurrence and distribution of plant-parasitic nematodes in Washington and Idaho vineyards. This research will be used by scientists and vineyard managers to better manage plant-parasitic nematodes in commercial vineyards.
Technical Abstract: Surveys were conducted in eastern Washington and Idaho to determine the plant-parasitic nematodes associated with wine grape (Vitis vinifera) vineyards. The most commonly encountered plant-parasitic nematodes in eastern Washington and Idaho wine grape vineyards were Meloidogyne hapla, Paratylenchus spp., and Xiphinema spp. (detected in > 50% of sampled vineyards), along with Pratylenchus spp., and Helicotylenchus spp. in Idaho. The frequency of occurrence of these plant-parasitic nematodes was consistently greater in Idaho compared to eastern Washington, except for M. hapla with a similar frequency of occurrence in both states. The types of ground cover or irrigation method utilized in vineyards and estimates of previous crop yields did not influence nematodes present in soil, but differences in plant-parasitic nematode communities were found among geographical areas (American Viticultural Areas, AVAs). Xiphinema spp. was more commonly associated with vineyards in the Horse Heaven Hills and Snake River Valley AVAs compared to Yakima Valley and Columbia Valley AVAs. Twenty-seven juice grape (Vitis labrusca) vineyards were sampled to enable a comparison of plant-parasitic nematode communities among red, and white wine grapes (V. vinifera), and juice grape varieties. Meloidogyne hapla and Xiphinema spp. were more commonly found in red and white wine grape vineyards than juice grape vineyards, while Mesocriconema xenoplax and Paratylenchus spp. were more commonly associated with white wine and juice grape vineyards compared to red wine grape vineyards. While plant-parasitic nematodes were commonly found in eastern Washington and Idaho vineyards, the impact of these plant-parasitic nematodes on wine grape productivity in this region remains to be determined.