Plant-Parasitic Nematodes Associated with Grapevines, Vitis vinifera, in Washington and Idaho

Abstract

Surveys were conducted in eastern Washington and Idaho to determine the plant-parasitic nematodes associated with winegrape (Vitis vinifera) vineyards. The most commonly encountered plant-parasitic nematodes in eastern Washington and Idaho winegrape vineyards were Meloidogyne hapla, Paratylenchus spp., and Xiphinema spp. (detected in >50% of sampled vineyards) with Pratylenchus spp. and Helicotylenchus spp. also commonly detected in Idaho. The frequency of occurrence of these plant-parasitic nematodes was consistently greater in Idaho compared to eastern Washington, except for M. hapla, which had a similar frequency of occurrence in both states. The types of groundcover or irrigation method used 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 than in the Yakima Valley and Columbia Valley AVAs. Twenty-seven juice grape (Vitis labruscana) vineyards were sampled to enable a comparison of plant-parasitic nematode communities among red and white winegrapes (V. vinifera) and juice grape varieties. Meloidogyne hapla and Xiphinema spp. were more commonly found in red and white winegrape vineyards than in juice grape vineyards, while Mesocriconema xenoplax and Paratylenchus spp. were more commonly associated with white wine and juice grape vineyards than with red winegrape vineyards. While plant-parasitic nematodes were commonly found in eastern Washington and Idaho vineyards, the impact of these plant-parasitic nematodes on winegrape productivity in this region remains to be determined.